Search

Retinoblastoma is the most frequent intraocular malignancy in children, originating from a maturing cone precursor in the developing retina. Little is known on the molecular basis underlying the biological and clinical behavior of this cancer. Here, using multi-omics data, we demonstrate the existence of two retinoblastoma subtypes. Subtype 1, of earlier onset, includes most of the heritable forms. It harbors few genetic alterations other than the initiating RB1 inactivation and corresponds to differentiated tumors expressing mature cone markers. By contrast, subtype 2 tumors harbor frequent recurrent genetic alterations including MYCN-amplification. They express markers of less differentiated cone together with neuronal/ganglion cell markers with marked inter- and intra-tumor heterogeneity. The cone dedifferentiation in subtype 2 is associated with stemness features including low immune and interferon response, E2F and MYC/MYCN activation and a higher propensity for metastasis. The recognition of these two subtypes, one maintaining a cone-differentiated state, and the other, more aggressive, associated with cone dedifferentiation and expression of neuronal markers, opens up important biological and clinical perspectives for retinoblastomas., Retinoblastoma is the most frequent intraocular paediatric malignancy whose molecular basis remains poorly understood. Here, the authors perform multi-omic analysis and identify two subtypes; one in a cone differentiated state and one more aggressive showing cone dedifferentiation and expressing neuronal markers.

Purpose: Pheochromocytomas and paragangliomas (PPGLs) are rare neuroendocrine tumors. Whereas most PPGLs are benign, up to 20% may become metastatic with SDHB- and FH-mutated tumors showing the higher risk. We aimed at determining the contribution of immortalization mechanisms to metastatic progression. Experimental Design: Immortalization mechanisms were investigated in 200 tumors. To identify telomerase (+) tumors, we analyzed genomic alterations leading to transcriptional activation of TERT comprising promoter mutations, hypermethylation and gain copy number. To identify tumors that activated the alternative lengthening of telomere (ALT) mechanism, we combined analyses of telomere length by slot blot, telomere heterogeneity by telomere FISH, and ATRX mutations by next-generation sequencing. Univariate/multivariate and metastasis-free survival (MFS) and overall survival (OS) analyses were carried out for assessment of risk factors and clinical outcomes. Results: Only 37 of 200 (18.5%) tumors achieved immortalization. Telomerase activation occurred in 12 metastatic tumors and was prevalent in SDHB-mutated paragangliomas (P = 2.42e−09). ALT features were present in 25 tumors, mostly pheochromocytomas, regardless of metastatic status or molecular group (P = 0.169), yet ATRX mutations were found preferentially in SDHB/FH-mutated metastatic tumors (P = 0.0014). Telomerase activation and ATRX mutations were independent factors of poor prognosis: MFS (hazard ratio, 48.2 and 33.1; P = 6.50E−07 and 1.90E−07, respectively); OS (hazard ratio, 97.4 and 44.1; P = 4.30E−03 and 2.00E−03, respectively) and were associated with worse MFS and OS (log-rank tests P < 0.0001). Conclusions: Assessment of telomerase activation and ATRX mutations could be used to identify metastatic PPGLs, particularly in tumors at high risk of progression.

Simple Summary Metastatic clear-cell renal cell carcinoma is characterized by heightened angiogenesis through increased expression of HIF-2α and VEGFR2. VEGFR tyrosine kinase inhibitors are a cornerstone of metastatic clear-cell renal cell carcinoma treatment, and new treatments targeting HIF-2α are currently under investigation. However, clinically useful biomarkers that can predict response to these treatments are lacking. MicroRNAs are small RNA molecules that interfere with gene translation. In this study, we identified four microRNAs that potentially interfere with the translation of VEGFR1 and/or VEGFR2 and are associated with tumor shrinkage and progression-free survival upon treatment with VEGFR-TKIs. These microRNAs might be predictive of response to VEGFR-TKIs. Moreover, we identified three microRNAs associated with HIF-2α expression and with tumor shrinkage and progression-free survival upon treatment with VEGFR-TKIs. These three microRNAs might be able to predict response not only to treatment with VEGFR-TKIs but possibly also to treatment with the upcoming HIF-2α inhibitor belzutifan. Abstract Metastatic clear-cell renal cell carcinoma (m-ccRCC) is characterized by increased hypoxia-induced factor (HIF)-2α and vascular endothelial growth factor receptor (VEGFR)-dependent angiogenesis through loss of function of the von Hippel–Lindau protein. VEGFR tyrosine kinase inhibitors (VEGFR-TKIs) are a cornerstone of m-ccRCC treatment, and new treatments targeting HIF-2α are currently under investigation. However, predictive biomarkers for these treatments are lacking. In this retrospective cohort study including 109 patients treated with VEGFR-targeted therapies as first-line treatment, we aimed to study the possible predictive function of microRNAs (miRNAs) targeting HIF-2α, VEGFR1 and VEGFR2. We selected miRNAs inversely correlated with HIF-2α, VEGFR1 and/or VEGFR2 expression and with predicted target sites in the respective genes and subsequently studied their impact on therapeutic outcomes. We identified four miRNAs (miR-34c-5p, miR-221-3p, miR-222-3p and miR-3529-3p) inversely correlated with VEGFR1 and/or VEGFR2 expression and associated with tumor shrinkage and progression-free survival (PFS) upon treatment with VEGFR-TKIs, highlighting the potential predictive value of these miRNAs. Moreover, we identified three miRNAs (miR-185-5p, miR-223-3p and miR-3529-3p) inversely correlated with HIF-2α expression and associated with tumor shrinkage and PFS upon treatment with VEGFR-TKIs. These three miRNAs can have a predictive value not only upon treatment with VEGFR-TKIs but possibly also upon treatment with the upcoming HIF-2α inhibitor belzutifan.

Immune checkpoint inhibitors (ICIs) have proved to be an effective treatment for up to 40% of muscle-invasive bladder cancer (MIBC), but there is still a need for better performing biomarkers allowing to improve prediction of response to ICI. Response to immunotherapy in soft-tissue sarcoma, melanoma and renal cell carcinoma have been recently linked to the presence of tertiary lymphoid structures (TLS) in the tumour. TLS are organised aggregates of T, B and dendritic cells, participating in adaptive antitumor immune response. The chemokine CXCL13 is involved in the formation of TLS, and is reported as a reliable transcriptomic marker of TLS.In this study, we sought to assess whether CXCL13 transcript expression can be a prognostic biomarker for ICI-treated MIBC patients and also investigated whether it can serve a biomarker of TLS in MIBC.We analysed transcriptomic data from three publicly available MIBC cohorts and evaluated pathological slides from the TCGA-BLCA cohort for TLS presence and stage of maturation.We showed that CXCL13 was independently associated with both prolonged survival (HR = 0.8, 95% CI [0.68-0.94]) and objective response (p 0.0001) in patients treated with ICI, at the difference of others immunological signatures. However, it was not a predictor for non-ICI-treated MIBC, suggesting a predictive effect of ICI efficacy. Finally, we validated that CXCL13 expression was correlated with tumour TLS in TCGA data set (p 0.001), and can serve as a marker of TLS in bladder cancer.These results support that CXCL13 expression, as a surrogate for tumour TLS, is a relevant candidate predictive biomarker of response to ICI for patients with advanced-stage bladder cancer.

The molecular landscape in non-muscle-invasive bladder cancer (NMIBC) is characterized by large biological heterogeneity with variable clinical outcomes. Here, we perform an integrative multi-omics analysis of patients diagnosed with NMIBC (n = 834). Transcriptomic analysis identifies four classes (1, 2a, 2b and 3) reflecting tumor biology and disease aggressiveness. Both transcriptome-based subtyping and the level of chromosomal instability provide independent prognostic value beyond established prognostic clinicopathological parameters. High chromosomal instability, p53-pathway disruption and APOBEC-related mutations are significantly associated with transcriptomic class 2a and poor outcome. RNA-derived immune cell infiltration is associated with chromosomally unstable tumors and enriched in class 2b. Spatial proteomics analysis confirms the higher infiltration of class 2b tumors and demonstrates an association between higher immune cell infiltration and lower recurrence rates. Finally, the independent prognostic value of the transcriptomic classes is documented in 1228 validation samples using a single sample classification tool. The classifier provides a framework for biomarker discovery and for optimizing treatment and surveillance in next-generation clinical trials., Multiple molecular profiling methods are required to study urothelial non-muscle-invasive bladder cancer (NMIBC) due to its heterogeneity. Here the authors integrate multi-omics data of 834 NMIBC patients, identifying a molecular subgroup associated with multiple alterations and worse outcomes.

Context:The number of prognostic markers for clear cell renal cell carcinoma (ccRCC) has been increasing regularly over the last 15 years, without being integrated and compared.Objective:Our goal was to perform a review of prognostic markers for ccRCC to lay the ground for their use in the clinics.Evidence Acquisition:PubMed database was searched to identify RNA and protein markers whose expression level was reported as associated with survival of ccRCC patients. Relevant studies were selected through cross-reading by two readers.Evidence Synthesis:We selected 249 studies reporting an association with prognostic of either single markers or multiple-marker models. Altogether, these studies were based on a total of 341 distinct markers and 13 multiple-marker models. Twenty percent of these markers were involved in four biological pathways altered in ccRCC: cell cycle, angiogenesis, hypoxia, and immune response. The main genes (VHL, PBRM1, BAP1, andSETD2) involved in ccRCC carcinogenesis are not the most relevant for assessing survival.Conclusion:Among single markers, the most validated markers wereKI67, BIRC5, TP53, CXCR4, andCA9. Of the multiple-marker models, the most famous model, ClearCode34, has been highly validated on several independent datasets, but its clinical utility has not yet been investigated.Patient Summary:Over the years, the prognosis studies have evolved from single markers to multiple-marker models. Our review highlights the highly validated prognostic markers and multiple-marker models and discusses their clinical utility for better therapeutic care.

GLI1 expression is broadly accepted as a marker of Hedgehog pathway activation in tumors. Efficacy of Hedgehog inhibitors is essentially limited to tumors bearing activating mutations of the pathway. GLI2, a critical Hedgehog effector, is necessary for GLI1 expression and is a direct transcriptional target of TGF-β/SMAD signaling. We examined the expression correlations of GLI1/2 with TGFB and HH genes in 152 distinct transcriptome datasets totaling over 23,500 patients and representing 37 types of neoplasms. Their prognostic value was measured in over 15,000 clinically annotated tumor samples from 26 tumor types. In most tumor types, GLI1 and GLI2 follow a similar pattern of expression and are equally correlated with HH and TGFB genes. However, GLI1/2 broadly share prognostic value with TGFB genes and a mesenchymal/EMT signature, not with HH genes. Our results provide a likely explanation for the frequent failure of anti-Hedgehog therapies in tumors, as they suggest a key role for TGF-β, not Hedgehog, ligands, in tumors with elevated GLI1/2-expression.

The chromosome translocations generating PAX3-FOXO1 and PAX7-FOXO1 chimeric proteins are the primary hallmarks of the paediatric fusion-positive alveolar subtype of Rhabdomyosarcoma (FP-RMS). Despite the ability of these transcription factors to remodel chromatin landscapes and promote the expression of tumour driver genes, they only inefficiently promote malignant transformation in vivo. The reason for this is unclear. To address this, we developed an in ovo model to follow the response of spinal cord progenitors to PAX-FOXO1s. Our data demonstrate that PAX-FOXO1s, but not wild-type PAX3 or PAX7, trigger the trans-differentiation of neural cells into FP-RMS-like cells with myogenic characteristics. In parallel, PAX-FOXO1s remodel the neural pseudo-stratified epithelium into a cohesive mesenchyme capable of tissue invasion. Surprisingly, expression of PAX-FOXO1s, similar to wild-type PAX3/7, reduce the levels of CDK-CYCLIN activity and increase the fraction of cells in G1. Introduction of CYCLIN D1 or MYCN overcomes this PAX-FOXO1-mediated cell cycle inhibition and promotes tumour growth. Together, our findings reveal a mechanism that can explain the apparent limited oncogenicity of PAX-FOXO1 fusion transcription factors. They are also consistent with certain clinical reports indicative of a neural origin of FP-RMS., Author summary The fusion-positive subtype of rhabdomyosarcoma (FP-RMS) is a rare malignant paediatric cancer, whose induction and evolution still remain to be deciphered. Out of the gross genetic aberrations found in these cancers, t(2:13) and t(1,13) chromosome translocations are the first to appear and lead to the expression of fusion proteins made of the DNA binding domains of either PAX3 or PAX7 and the transactivation domain of FOXO1. Both PAX3-FOXO1 and PAX7-FOXO1 have a strong impact on gene transcription, yet they only inefficiently promote the transformation of healthy cells into tumorigenic cells. To address this issue, we have used chick embryos to monitor in vivo the early response of cells to PAX-FOXO1 chimeric proteins. We showed that both proteins, but not the normal PAX3 and PAX7, transform neural cells into cells with FP-RMS molecular features. The PAX-FOXO1s also force polarized epithelial neural cells to adopt a mesenchymal phenotype with tissue invasive properties. However, the PAX-FOXO1s inhibit cell division and hence tumour growth. Genetically re-activating core cell cycle regulators rescues PAX-FOXO1 mediated cell cycle inhibition. Together, our findings bring further support to the idea that the PAX-FOXO1s are stricto sensu oncoproteins, whose oncogenicity is limited by negative effects on cell cycle.

Benign adrenal tumors cover a spectrum of lesions with distinct morphology and steroid secretion. Current classification is empirical. Beyond a few driver mutations, pathophysiology is not well understood. Here, a pangenomic characterization of benign adrenocortical tumors is proposed, aiming at unbiased classification and new pathophysiological insights. Benign adrenocortical tumors (n = 146) were analyzed by transcriptome, methylome, miRNome, chromosomal alterations and mutational status, using expression arrays, methylation arrays, miRNA sequencing, SNP arrays, and exome or targeted next-generation sequencing respectively. Pathological and hormonal data were collected for all tumors. Pangenomic analysis identifies four distinct molecular categories: (1) tumors responsible for overt Cushing, gathering distinct tumor types, sharing a common cAMP/PKA pathway activation by distinct mechanisms; (2) adenomas with mild autonomous cortisol excess and non-functioning adenomas, associated with beta-catenin mutations; (3) primary macronodular hyperplasia with ARMC5 mutations, showing an ovarian expression signature; (4) aldosterone-producing adrenocortical adenomas, apart from other benign tumors. Epigenetic alterations and steroidogenesis seem associated, including CpG island hypomethylation in tumors with no or mild cortisol secretion, miRNA patterns defining specific molecular groups, and direct regulation of steroidogenic enzyme expression by methylation. Chromosomal alterations and somatic mutations are subclonal, found in less than 2/3 of cells. New pathophysiological insights, including distinct molecular signatures supporting the difference between mild autonomous cortisol excess and overt Cushing, ARMC5 implication into the adreno-gonadal differentiation faith, and the subclonal nature of driver alterations in benign tumors, will orient future research. This first genomic classification provides a large amount of data as a starting point.

Quantifying tissue-infiltrating immune and stromal cells provides clinically relevant information for various diseases. While numerous methods can quantify immune or stromal cells in human tissue samples from transcriptomic data, few are available for mouse studies. We introduce murine Microenvironment Cell Population counter (mMCP-counter), a method based on highly specific transcriptomic markers that accurately quantify 16 immune and stromal murine cell populations. We validated mMCP-counter with flow cytometry data and showed that mMCP-counter outperforms existing methods. We showed that mMCP-counter scores are predictive of response to immune checkpoint blockade in cancer mouse models and identify early immune impacts of Alzheimer’s disease.

Funder: Spanish Ministry of Science, Innovation, and University. BFU2016-80570-R, Funder: Cancer Research UK (CRUK); doi: https://doi.org/10.13039/501100000289, Funder: Fundación Científica Asociación Española Contra el Cáncer (Scientific Foundation, Spanish Association Against Cancer); doi: https://doi.org/10.13039/501100002704, As the catalog of oncogenic driver mutations is expanding, it becomes clear that alterations in a given gene might have different functions and should not be lumped into one class. The transcription factor GATA3 is a paradigm of this. We investigated the functions of the most common GATA3 mutation (X308_Splice) and five additional mutations, which converge into a neoprotein that we called “neoGATA3,” associated with excellent prognosis in patients. Analysis of available molecular data from >3000 breast cancer patients revealed a dysregulation of the ER-dependent transcriptional response in tumors carrying neoGATA3-generating mutations. Mechanistic studies in vitro showed that neoGATA3 interferes with the transcriptional programs controlled by estrogen and progesterone receptors, without fully abrogating them. ChIP-Seq analysis indicated that ER binding is reduced in neoGATA3-expressing cells, especially at distal regions, suggesting that neoGATA3 interferes with the fine tuning of ER-dependent gene expression. This has opposite outputs in distinct hormonal context, having pro- or anti-proliferative effects, depending on the estrogen/progesterone ratio. Our data call for functional analyses of putative cancer drivers to guide clinical application.

The molecular landscape in non-muscle-invasive bladder cancer (NMIBC) is characterized by large biological heterogeneity with variable clinical outcomes. Here, we performed a large integrative multi-omics analysis of patients diagnosed with NMIBC (n=834). Transcriptomic analysis identified four classes (1, 2a, 2b and 3) reflecting tumor biology and disease aggressiveness. Both transcriptome-based subtyping and the level of chromosomal instability provided independent prognostic value beyond established prognostic clinicopathological parameters. High chromosomal instability, p53-pathway disruption and APOBEC-related mutations were significantly associated with transcriptomic class 2a and poor outcome. RNA-derived immune cell infiltration was associated with chromosomally unstable tumors and enriched in class 2b. Spatial proteomics analysis confirmed the higher infiltration of class 2b tumors and demonstrated an association between higher immune cell infiltration and lower recurrence rates. Finally, a single-sample classification tool was built and the independent prognostic value of the transcriptomic classes was documented in 1306 validation samples. The classifier provides a framework for novel biomarker discovery and for optimizing treatment and surveillance in next-generation clinical trials.

Cadherins form a large and pleiotropic superfamily of membranous proteins sharing Ca2+-binding repeats. While the importance of classic cadherins such as E- or N-cadherin for tumorigenesis is acknowledged, there is much less information about other cadherins that are merely considered as tissue-specific adhesion molecules. Here, we focused on the atypical cadherin MUCDHL that stood out for its unusual features and unique function in the gut. Analyses of transcriptomic data sets (n > 250) established that MUCDHL mRNA levels are down-regulated in colorectal tumors. Importantly, the decrease of MUCDHL expression is more pronounced in the worst-prognosis subset of tumors and is associated with decreased survival. Molecular characterization of the tumors indicated a negative correlation with proliferation-related processes (e.g., nucleic acid metabolism, DNA replication). Functional genomic studies showed that the loss of MUCDHL enhanced tumor incidence and burden in intestinal tumor-prone mice. Extensive structure/function analyses revealed that the mode of action of MUCDHL goes beyond membrane sequestration of s-catenin and targets through its extracellular domain key oncogenic signaling pathways (e.g., EGFR, AKT). Beyond MUCDHL, this study illustrates how the loss of a gene critical for the morphological and functional features of mature cells contributes to tumorigenesis by dysregulating oncogenic pathways.

Stage T1 bladder cancers have the highest progression and recurrence rates of all non-muscle-invasive bladder cancers (NMIBCs). Most T1 cancers are treated with bacillus Calmette-Guerin (BCG), but many will progress or recur, and some T1 patients will die from bladder cancer. Particularly aggressive tumors could be treated with early cystectomy. To better understand the molecular heterogeneity of T1 cancers, we performed transcriptome profiling and unsupervised clustering, and identified five consensus subtypes of T1 tumors treated with repeat transurethral resection (reTUR) and induction and maintenance BCG. The T1-LumGU subtype was associated with carcinoma in situ (CIS; six/13, 46% of all CIS), had high E2F1 and EZH2 expression, and was enriched in E2F target and G2M checkpoint hallmarks. The T1-Inflam subtype was inflamed and infiltrated with immune cells. While most T1 tumors were classified as luminal papillary, the T1-TLum subtype had the highest median luminal papillary score and FGFR3 expression, no recurrence events, and the fewest copy number gains. T1-Myc and T1-Early subtypes had the most recurrences (14/30 within 24 mo), the highest median MYC expression, and, when combined, had significantly worse recurrence-free survival than the other three subtypes. T1-Early had five (38%) recurrences within the first 6 mo of BCG, and repressed IFN-α and IFN-γ hallmarks and inflammation. We developed a single-patient T1 classifier and validated our subtype biology in a second cohort of T1 tumors. Future research will be necessary to validate the proposed T1 subtypes and to determine if therapies can be individualized for each subtype. PATIENT SUMMARY: We identified and characterized expression subtypes of high-grade stage T1 bladder cancer that are biologically heterogeneous and have variable responses to bacillus Calmette-Guerin treatment. We validated the subtypes and describe a single-patient classifier.

Quantifying tissue-infiltrating immune and stromal cells provides clinically relevant information for various diseases, notably cancer. While numerous methods allow to quantify immune or stromal cells in human tissue samples based on transcriptomic data, very few are available for mouse studies. Here, we introduce murine Microenvironment Cell Population counter (mMCP-counter), a method based on highly specific transcriptomic markers that allow to accurately quantify 12 immune and 4 stromal murine cell populations. We validated mMCP-counter with flow cytometry data. We also showed that mMCP-counter outperforms existing methods. We showed in mouse models of mesothelioma and kidney cancer that mMCP-counter quantification scores are predictive of response to immune checkpoint blockade Finally, we illustrated mMCP-counter’s potential to analyze immune impacts of Alzheimer’s disease. mMCP-counter is available as an R package from GitHub: https://github.com/cit-bioinfo/mMCP-counter.

Soft-tissue sarcomas represent a heterogeneous group of cancer, with more than 50 histological subtypes1,2. The clinical presentation of patients with different subtypes is often atypical, and responses to therapies such as immune checkpoint blockade vary widely3,4. To explain this clinical variability, here we study gene expression profiles in 608 tumours across subtypes of soft-tissue sarcoma. We establish an immune-based classification on the basis of the composition of the tumour microenvironment and identify five distinct phenotypes: immune-low (A and B), immune-high (D and E), and highly vascularized (C) groups. In situ analysis of an independent validation cohort shows that class E was characterized by the presence of tertiary lymphoid structures that contain T cells and follicular dendritic cells and are particularly rich in B cells. B cells are the strongest prognostic factor even in the context of high or low CD8+ T cells and cytotoxic contents. The class-E group demonstrated improved survival and a high response rate to PD1 blockade with pembrolizumab in a phase 2 clinical trial. Together, this work confirms the immune subtypes in patients with soft-tissue sarcoma, and unravels the potential of B-cell-rich tertiary lymphoid structures to guide clinical decision-making and treatments, which could have broader applications in other diseases. Immune profiling of the tumour microenvironment of soft-tissue sarcoma identifies a group of patients with high levels of B-cell infiltration and tertiary lymphoid structures that have improved survival and a high response rate to immune checkpoint blockade therapy.

Background Clear-cell renal-cell carcinoma (ccRCC) is characterized by loss of a functional Von Hippel–Lindau (VHL) protein. We investigated the potential of 3 single nucleotide polymorphisms (SNPs) in VHL as biomarkers in metastatic ccRCC (m-ccRCC) patients treated with vascular endothelial growth factor receptor (VEGFR) tyrosine kinase inhibitors (TKIs). Patients and Methods We genotyped 3 VHL SNPs in 199 m-ccRCC patients: rs1642742 T > C, rs1642743 A > G, and rs1678607 C > A. Primary end points were response rate (RR), progression-free survival (PFS), and overall survival (OS) after start of first-line TKI. RR was compared with Fisher’s exact test, and PFS and OS with Kaplan-Meier analysis and multivariable Cox regression. Secondary end points were association with VHL promotor hypermethylation, VHL mutation status, VHL loss of heterozygosity, ≥ 25% sarcomatoid dedifferentiation, and expression of genes implicated in angiogenesis and immunoresponse (Fisher’s exact test and unpaired t tests). Results The minor alleles of rs1642742 and rs1642743, known to be in close linkage disequilibrium, were associated with poor outcome, following a recessive pattern. For the rs1642742 CC versus TT/TC genotype, OS was 11 versus 26 months (hazard ratio = 2.3; 95% confidence interval, 1.2-6.6; P = .015). For the rs1642743 GG versus AA/AG genotype, OS was 15 versus 28 months (hazard ratio = 2.6; 95% confidence interval, 1.4-5.0; P = .004). After multivariable analysis, both remained linked with poor OS (P = .018 and P = .009, respectively). There was a trend toward shorter PFS and poorer RR. Both SNPs were associated with ≥ 25% sarcomatoid dedifferentiation (P = .037 and .006, respectively). No significant results were found for rs1678607. Conclusion rs1642742 and rs1642743 are candidate biomarkers for poor OS in m-ccRCC patients receiving first-line VEGFR-TKI. They are associated with higher levels of sarcomatoid dedifferentiation.

International audience; Background: We previously described 4 molecular subtypes of metastatic clear cell renal cell carcinoma (mccRCC), named ccrcc1-4 (Beuselinck et al, 2015). These have both prognostic and predictive value for patients treated with first-line sunitinib, with distinctive objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). The ccrcc2 and ccrcc3 tumors have the best outcomes, followed by ccrcc1 and then ccrcc4. We hypothesized that these molecular subtypes would show similar outcomes with first-line pazopanib treatment.Patients and methods: We classified 28 mccRCC tumors treated with pazopanib as first-line therapy, as described previously. The primary endpoints were PFS and OS from the start of pazopanib. A secondary endpoint was ORR. Because there were only 2 ccrcc3 tumors, they were pooled with the ccrcc2 tumors for outcome analysis.Results: PFS was 9 months for the ccrcc2 and ccrcc3 tumors, 5 months for ccrcc1 tumors, and 3 months for the ccrcc4 tumors (P = .011). The corresponding OS duration was 69, 19, and 5 months (P = .003). The corresponding ORR was 50%, 33%, and 0%. The corresponding mean tumor size decreased by 34%, 6%, and 2% (P = .032). The ccrcc1-4 classification was a stronger predictor of outcome than the International Metastatic Renal Cell Carcinoma Database Consortium score on univariate analysis (P = .011 vs. P = .094 for PFS and P = .003 vs. .013 for OS). Both remained independent on bivariate analysis.Conclusion: The molecular subtypes of mccRCC are associated with outcome on pazopanib as first-line therapy. The prognostic and predictive value of the ccrcc1-4 molecular classification requires validation in prospective trials.

Chondrosarcomas are primary cancers of cartilaginous tissue with highly contrasting prognoses. These tumors are defined by recurrent mutations in the IDH genes and other genetic alterations including inactivation of CDKN2A and COL2A1; however, these have no clinical value. Here we use multi-omics molecular profiles from a series of cartilage tumors and find an mRNA classification that identifies two subtypes of chondrosarcomas defined by a balance in tumor differentiation and cell cycle activation. The microRNA classification reveals the importance of the loss of expression of the 14q32 locus in defining the level of malignancy. Finally, DNA methylation is associated with IDH mutations. We can use the multi-omics classifications to predict outcome. We propose an mRNA-only classifier to reproduce the integrated multi-omics classification, and its application to relapsed tumor samples shows the progressive nature of the classification. Thus, it may be possible to use mRNA-based signatures to detect patients with high-risk chondrosarcomas., Chondrosarcomas are heterogenous tumours of the bone cartilage and have highly variable prognoses. Here, the authors perform a multi-omics analysis, revealing molecular features that can stratify clinical outcomes.

As the catalogue of oncogenic driver mutations is expanding, it is becoming clear that alterations in a given gene should not be lumped into one single class, since they might have different functions. The transcription factorGATA3is a paradigm of this. Here, we address the functions of the most commonGATA3mutation (X308_Splice) which generates a neoprotein that we designate as neoGATA3, associated with good patient prognosis. Based on extensive analyses of molecular and clinical data from approximately 3000 breast cancer patients, supported by mechanistic studiesin vitro, we show that neoGATA3 interferes with the transcriptional programs controlled by estrogen and progesterone receptors, without fully abrogating them. This has opposite outputs in the pre- or post-menopausal hormonal context, having pro- or anti-proliferative effects, respectively. NeoGATA3 is an example of a context- and stage-dependent driver mutation. Our data call for functional analyses of putative cancer drivers to guide clinical application.

The management of locally advanced head and neck squamous cell carcinoma (HNSCC) with Cetuximab, a monoclonal antibody targeting the epidermal growth factor receptor (EGFR), achieves only moderate response rates, and clinical trials that evaluated EGFR-blockade with tyrosine kinase inhibitors (TKI) yielded disappointing results. Inter-tumor heterogeneity may hinder the therapeutic efficiency of anti-EGFR treatments. HNSCC heterogeneity was addressed in several studies, which all converged towards the definition of molecular subgroups. They include the basal subgroup, defined by the deregulated expression of factors involved in the EGFR signaling pathway, including the epiregulin EGFR ligand encoded by the EREG gene. These observations indicate that basal tumors could be more sensitive to anti-EGFR treatments. To test this hypothesis, we performed a screen of a representative collection of basal versus non-basal HNSCC cell lines for their sensitivity to several anti-EGFR drugs (Cetuximab, Afatinib, and Gefitinib), tested as monotherapy or in combination with drugs that target closely-linked pathways [Mitogen-activated protein kinase kinase/ extracellular signal&ndash, regulated kinases (MEK), mammalian Target of Rapamycine (mTOR) or Human Epidermal growth factor Receptor 2 (HER2)]. Basal-like cell lines were found to be more sensitive to EGFR blockade alone or in combination with treatments that target MEK, mTOR, or HER2. Strikingly, the basal-like status was found to be a better predictor of cell response to EGFR blockade than clinically relevant mutations [e.g., cyclin-dependent kinase Inhibitor 2A (CDKN2A)]. Interestingly, we show that EGFR blockade inhibits EREG expression, and that EREG knock-down decreases basal cell clonogenic survival, suggesting that EREG expression could be a predictive functional marker of sensitivity to EGFR blockade in basal-like HNSCC.

Clear-cell renal cell carcinoma (ccRCC) possesses an unmet medical need, particularly at the metastatic stage, when surgery is ineffective. Complement is a key factor in tissue inflammation, favoring cancer progression through the production of complement component 5a (C5a). However, the activation pathways that generate C5a in tumors remain obscure. By data mining, we identified ccRCC as a cancer type expressing concomitantly high expression of the components that are part of the classical complement pathway. To understand how the complement cascade is activated in ccRCC and impacts patients' clinical outcome, primary tumors from three patient cohorts (n = 106, 154, and 43), ccRCC cell lines, and tumor models in complement-deficient mice were used. High densities of cells producing classical complement pathway components C1q and C4 and the presence of C4 activation fragment deposits in primary tumors correlated with poor prognosis. The in situ orchestrated production of C1q by tumor-associated macrophages (TAM) and C1r, C1s, C4, and C3 by tumor cells associated with IgG deposits, led to C1 complex assembly, and complement activation. Accordingly, mice deficient in C1q, C4, or C3 displayed decreased tumor growth. However, the ccRCC tumors infiltrated with high densities of C1q-producing TAMs exhibited an immunosuppressed microenvironment, characterized by high expression of immune checkpoints (i.e., PD-1, Lag-3, PD-L1, and PD-L2). Our data have identified the classical complement pathway as a key inflammatory mechanism activated by the cooperation between tumor cells and TAMs, favoring cancer progression, and highlight potential therapeutic targets to restore an efficient immune reaction to cancer.

International audience; We determined the proportions of epithelioid-like and sarcomatoid-like cellular entities within malignant pleural mesothelioma samples, by deconvolution of their transcriptomes. These proportions are associated with prognosis and may guide therapeutic strategies. This novel approach describes both intra- and inter-tumor heterogeneity and provides a new way of thinking about cancer pathology.

Data from the Cancer Genome Atlas (TCGA) are now easily accessible through web-based platforms with tools to assess the prognostic value of molecular alterations. Pancreatic tumors have heterogeneous biology and aggressiveness ranging from the deadly adenocarcinoma (PDAC) to the better prognosis, neuroendocrine tumors. We assessed the availability of the pancreatic cancer TCGA data (TCGA_PAAD) from several repositories and investigated the nature of each sample and how non-PDAC samples impact prognostic biomarker studies. While the clinical and genomic data (n = 185) were fairly consistent across all repositories, RNAseq profiles varied from 176 to 185. As a result, 35 RNAseq profiles (18.9%) corresponded to a normal, inflamed pancreas or non-PDAC neoplasms. This information was difficult to obtain. By considering gene expression data as continuous values, the expression of the 5312 and 4221 genes were significantly associated with the progression-free and overall survival respectively. Considering the cohort was not curated, only 4 and 14, respectively, had prognostic value in the PDAC-only cohort. Similarly, mutations in key genes or well-described miRNA lost their prognostic significance in the PDAC-only cohort. Therefore, we propose a web-based application to assess biomarkers in the curated TCGA_PAAD dataset. In conclusion, TCGA_PAAD curation is critical to avoid important biological and clinical biases from non-PDAC samples.

Clear-cell renal cell carcinomas (ccRCC) are characterized by hyper-vascularization and can respond to vascular endothelial growth factor receptor (VEGFR) inhibitors such as sunitinib. We aimed to study the predictive value of the expression of genes in the hypoxia induced factor (HIF) - vascular endothelial growth factor (VEGF) - VEGFR-pro-angiogenic pathway in metastatic ccRCC (m-ccRCC) patients treated with sunitinib and the correlation between the expression of these genes and the molecular ccrcc-classification, the expression of genes involved in the immune-suppressive microenvironment and Von Hippel-Lindau (VHL) - and Polybromo-1 (PBRM1) - mutational status.m-ccRCC patients treated with sunitinib as first-line targeted therapy were included. Gene expression was studied in the primary nephrectomy sample by qRT-PCR, VHL- and PBRM1-mutational status by sequencing. Response rate by RECIST, progression-free survival (PFS) and overall survival (OS) were study endpoints.One hundred and four patients were included. On multivariate-analysis, HIF2A-, platelet derived growth factor receptor beta (PDGFRB)-, VEGFC-, VEGFR1- and VEGFR2-expression were correlated with PFS and HIF1A-, HIF2A-, VEGFR1- and VEGFR2-expression with OS. VEGFR2-expression showed the strongest association with outcome, being significantly correlated with all outcome parameters. HIF2A, VEGFA, VEGFR1, VEGFR2 and VEGFR3 were highly expressed in the transcriptomic ccrcc2-subtype of tumors, known to be highly sensitive to sunitinib. In the total tumor series, there was no correlation nor inverse correlation between the expression of genes involved in angiogenesis and in the immune-suppressive microenvironment. In tumors with a bi-allelic PBRM1-inactivation, HIF2A-, VEGFA-, VEGFR1- and VEGFR2-expression were higher, compared to tumors with one or two functional PBRM1-alleles.Intratumoral expression of genes involved in the HIF-VEGF-VEGFR-pro-angiogenic pathway, especially VEGFR2, is associated with favorable outcome on sunitinib in m-ccRCCs. Several genes involved in this pathway are upregulated in the molecular ccrcc2-subgroup, which usually responds well to sunitinib.

Pulmonary large-cell neuroendocrine carcinomas (LCNECs) have similarities with other lung cancers, but their precise relationship has remained unclear. Here we perform a comprehensive genomic (n = 60) and transcriptomic (n = 69) analysis of 75 LCNECs and identify two molecular subgroups: “type I LCNECs” with bi-allelic TP53 and STK11/KEAP1 alterations (37%), and “type II LCNECs” enriched for bi-allelic inactivation of TP53 and RB1 (42%). Despite sharing genomic alterations with adenocarcinomas and squamous cell carcinomas, no transcriptional relationship was found; instead LCNECs form distinct transcriptional subgroups with closest similarity to SCLC. While type I LCNECs and SCLCs exhibit a neuroendocrine profile with ASCL1high/DLL3high/NOTCHlow, type II LCNECs bear TP53 and RB1 alterations and differ from most SCLC tumors with reduced neuroendocrine markers, a pattern of ASCL1low/DLL3low/NOTCHhigh, and an upregulation of immune-related pathways. In conclusion, LCNECs comprise two molecularly defined subgroups, and distinguishing them from SCLC may allow stratified targeted treatment of high-grade neuroendocrine lung tumors., The molecular nature of large-cell neuroendocrine lung carcinomas (LCNEC) has remained unclear. Here, the authors show LCNECs represent a distinct transcriptional subgroup among lung cancers and comprise two molecular subgroups, type I (TP53 and STK11/KEAP1 alterations) and type II (TP53 and RB1 inactivation).

International audience; BACKGROUND & AIMS: Genomic studies have revealed subtypes of pancreatic ductal adenocarcinoma (PDA) based on their molecular features, but different studies have reported different classification systems. It is a challenge to obtain high-quality, freshly frozen tissue for clinical analysis and determination of PDA subtypes. We aimed to redefine subtypes of PDA using a large number of formalin-fixed and paraffin-embedded PDA samples, which are more amenable to routine clinical evaluation. METHODS: We collected PDA samples from 309 consecutive patients who underwent surgery from September 1996 through December 2010 at 4 academic hospitals in Europe; nontumor tissue samples were not included. Samples were formalin fixed and paraffin embedded. DNA and RNA were isolated; gene expression, targeted DNA sequencing, and immunohistochemical analyses were performed. We used independent component analysis to deconvolute normal, tumor, and microenvironment transcriptome patterns in samples. We devised classification systems from an unsupervised analysis using a consensus clustering approach of our data set after removing normal contamination components. We associated subtypes with overall survival and disease-free survival of patients using Cox proportional hazards regression with estimation of hazard ratios and 95% confidence interval. We used The Cancer Genome Consortium and International Cancer Genome Consortium PDA data sets as validation cohorts. RESULTS: We validated the previously reported basal-like and classical tumor-specific subtypes of PDAs. We identified features of the PDA, including microenvironment gene expression patterns, that allowed tumors to be categorized into 5 subtypes, called pure basal like, stroma activated, desmoplastic, pure classical, and immune classical. These PDA subtypes have features of cancer cells and immune cells that could be targeted by pharmacologic agents. Tumor subtypes were associated with patient outcomes, based on analysis of our data set and the International Cancer Genome Consortium and The Cancer Genome Consortium PDA data sets. We also observed an exocrine signal associated with acinar cell contamination (from pancreatic tissue). CONCLUSIONS: We identified a classification system based on gene expression analysis of formalin-fixed PDA samples. We identified 5 PDA subtypes, based on features of cancer cells and the tumor microenvironment. This system might be used to select therapies and predict patient outcomes. We found evidence that the previously reported exocrine-like (called ADEX) tumor subtype resulted from contamination with pancreatic acinar cells. ArrayExpress accession number: E-MTAB-6134.

Background Metastasectomy is routinely performed in selected patients with metastatic clear-cell renal cell carcinoma (ccRCC) as an alternative to systemic therapy. In the absence of randomized trials, the benefit and best way of patient selection remain unclear. Earlier, we described four molecular ccRCC-subtypes (ccrcc1–4) that have a prognostic and predictive value upon first-line sunitinib or pazopanib. Objective Assess the prognostic value of ccrcc1–4 subtypes after complete metastasectomy. (1) Compare outcomes of good-prognosis ccrccc2&3-tumors with intermediate/poor-prognosis ccrcc1&4-tumors. (2) Compare outcomes of the four subtypes separately. Design, setting, and participants Single-center retrospective study (1995–2017), assessing 43 ccRCC patients undergoing complete metastasectomy without systemic treatment. Intervention Molecular subtype determined with established 35-gene expression classifier. Outcome measurements and statistical analysis Median disease-free survival (DFS), time to systemic therapy, cancer-specific (CSS) and overall survival (OS) from metastasectomy, estimated with Kaplan-Meier method and tested against other predictors with multivariable Cox regression. Results and limitations Median DFS was 23 mo for ccrcc2&3-tumors versus 9 mo for ccrcc1&4-tumors ( p =0.011, hazard ratio [HR]=2.6). Median time to systemic therapy was 92 mo versus 28 mo ( p =0.003, HR=3.3). Median CSS was 133 mo versus 50 mo ( p p =0.011, HR=2.5). The classification remained independent upon multivariable analysis. Outcomes remained significantly different when comparing four subtypes separately. The intrinsic heterogeneity of expression profiles is a limitation of this approach. Conclusion Even after clinical patient selection, patients with a ccrcc1- or ccrcc4-tumor are at a higher risk of relapse after complete metastasectomy. Patients with a ccrcc2- or ccrcc3-tumor usually experience a long DFS. These results need validation in a larger cohort to establish the subtypes as prognostic marker. Patient summary Metastasectomy is recommended for some patients with metastatic clear-cell kidney cancer; however, we do not know who will benefit the most. We show that molecular subtypes increase the possibility to predict which patients are at risk for early relapse after metastasectomy and who may benefit more from other treatment options.

SUMMARY Preclinical models based on patient-derived xenografts have remarkable specificity in distinguishing transformed human tumor cells from non-transformed murine stromal cells computationally. We obtained 29 pancreatic ductal adenocarcinoma (PDAC) xenografts from either resectable or non-resectable patients (surgery and endoscopic ultrasound-guided fine-needle aspirate, respectively). Extensive multiomic profiling revealed two subtypes with distinct clinical outcomes. These subtypes uncovered specific alterations in DNA methylation and transcription as well as in signaling pathways involved in tumor-stromal cross-talk. The analysis of these pathways indicates therapeutic opportunities for targeting both compartments and their interactions. In particular, we show that inhibiting NPC1L1 with Ezetimibe, a clinically available drug, might be an efficient approach for treating pancreatic cancers. These findings uncover the complex and diverse interplay between PDAC tumors and the stroma and demonstrate the pivotal role of xenografts for drug discovery and relevance to PDAC., In Brief Nicolle et al. present a genomic analysis of pancreatic cancer xenografts showing that tumor subtypes are defined by specific epigenetic, transcriptional, and stromal landscapes. They reveal potential therapeutic targets through analysis of signaling cross-talk between tumor and stromal cells.

Purpose: To better define malignant pleural mesothelioma (MPM) heterogeneity and identify molecular subtypes of MPM, we focus on the tumor suppressor gene LATS2, a member of the Hippo signaling pathway, which plays a key role in mesothelial carcinogenesis. Experimental Design: Sixty-one MPM primary cultures established in our laboratory were screened for mutations in LATS2. Gene inactivation was modeled using siRNAs. Gene and protein expressions were analyzed by quantitative RT-PCR, Western blot analysis, and reverse phase protein array. Cell proliferation, viability, apoptosis, mobility, and invasion were determined after siRNA knockdown or YAP (verteporfin), mTOR (rapamycin), and mTOR/PI3K/AKT (PF-04691502) inhibitor treatment. Results: The LATS2 gene was altered in 11% of MPM by point mutations and large exon deletions. Genetic data coupled with transcriptomic data allowed the identification of a new MPM molecular subgroup, C2LN, characterized by a co-occurring mutation in the LATS2 and NF2 genes in the same MPM. MPM patients of this subgroup presented a poor prognosis. Coinactivation of LATS2 and NF2 leads to loss of cell contact inhibition between MPM cells. Hippo signaling pathway activity, mTOR expression, and phosphorylation were altered in the C2LN MPM subgroup. MPMs of this new subgroup show higher sensitivity to PF-04691502 inhibitor. The MOK gene was identified as a potential biomarker of the C2LN MPM subgroup and PF-04691502 sensitivity. Conclusions: We identified a new MPM molecular subgroup that shares common genetic and transcriptomic characteristics. Our results made it possible to highlight a greater sensitivity to an anticancer compound for this MPM subgroup and to identify a specific potential biomarker. Clin Cancer Res; 23(12); 3191–202. ©2016 AACR.

International audience; Tumors are highly heterogeneous tissues where malignant cells are surrounded by and interact with a complex tumor microenvironment (TME), notably composed of a wide variety of immune cells, as well as vessels and fibroblasts. As the dialectical influence between tumor cells and their TME is known to be clinically crucial, we need tools that allow us to study the cellular composition of the microenvironment. In this focused research review, we report MCP-counter, a methodology based on transcriptomic markers that assesses the proportion of several immune and stromal cell populations in the TME from transcriptomic data, and we highlight how it can provide a way to decipher the complex mechanisms at play in tumors. In several malignancies, MCP-counter scores have been used to show various prognostic impacts of the TME, which we also show to be linked with the mutational burden of tumors. We also compared established molecular classifications of colorectal cancer and clear-cell renal cell carcinoma with the output of MCP-counter, and show that molecular subgroups have different TME profiles, and that these profiles are consistent within a given subgroup. Finally, we provide insights as to how knowing the TME composition may shape patient care in the near future.

Due to the phenotypic and molecular diversity of hepatocellular carcinomas (HCC), it is a challenge to determine a patient's prognosis. We aimed to identify new prognostic markers of patients with HCC treated by liver resection.We collected 314 HCC samples from patients at Bordeaux (1998-2007) and Créteil (2003-2007) hospitals in France. We analyzed the gene expression patterns of the tumors and compared expression patterns with patient survival times. Using the coefficient and regression formula of the multivariate Cox model, we identified a "5-gene score" associated with survival times. This molecular score was then validated in 2 groups of patients from Europe and the United States (n = 213) and China (n = 221).The 5-gene score, based on combined expression level of HN1, RAN, RAMP3, KRT19, and TAF9, was associated with disease-specific survival times of 189 patients with resected HCC in Bordeaux (hazard ratio = 3.5; 95% confidence interval: 1.9-6.6; P.0001). The association between the 5-gene score and disease-specific survival was validated in an independent cohort of 125 patients in Créteil (hazard ratio = 2.3; 95% confidence interval: 1.1-4.9; P.0001). The 5-gene score more accurately predicted patient outcomes than gene expression signatures reported previously. In multivariate analyses, the 5-gene score was associated with disease-specific survival, independent of other clinical and pathology feature of HCC. Disease-specific survival was also predicted by combining data on microvascular invasion, the Barcelona Clinic Liver Cancer classification system, and the 5-gene score in a nomogram. The prognostic accuracy of the 5-gene score was further validated in European and US patients with hepatitis C, cirrhosis, and HCC (overall survival P = .002) and in Asian patients with HCC with hepatitis B (overall survival, P = .02). Combining the 5-gene score with the expression pattern of 186 genes in corresponding cirrhotic tissues increased its prognostic accuracy.The molecular 5-gene score is associated with outcomes of patients with HCC treated by resection in different clinical settings worldwide. This new biomarker should be tested in clinical trials to stratify patients in therapeutic decisions.

SummaryParagangliomas are neuroendocrine tumors frequently associated with mutations in RET, NF1, VHL, and succinate dehydrogenase (SDHx) genes. Methylome analysis of a large paraganglioma cohort identified three stable clusters, associated with distinct clinical features and mutational status. SDHx-related tumors displayed a hypermethylator phenotype, associated with downregulation of key genes involved in neuroendocrine differentiation. Succinate accumulation in SDH-deficient mouse chromaffin cells led to DNA hypermethylation by inhibition of 2-OG-dependent histone and DNA demethylases and established a migratory phenotype reversed by decitabine treatment. Epigenetic silencing was particularly severe in SDHB-mutated tumors, potentially explaining their malignancy. Finally, inactivating FH mutations were identified in the only hypermethylated tumor without SDHx mutations. These findings emphasize the interplay between the Krebs cycle, epigenomic changes, and cancer.

IF 12.589; International audience; BackgroundImmune checkpoint (ICK) expression might represent a surrogate measure of tumor-infiltrating T cell (CTL) exhaustion and therefore be a more accurate prognostic biomarker for colorectal cancer (CRC) patients than CTL enumeration as measured by the Immunoscore.MethodsThe expression of ICKs, Th1, CTLs, cytotoxicity-related genes, and metagenes, including Immunoscore-like metagenes, were evaluated in three independent cohorts of CRC samples (260 microsatellite instable [MSI], 971 non-MSI). Their associations with patient survival were analyzed by Cox models, taking into account the microsatellite instability (MSI) status and affiliation with various Consensus Molecular Subgroups (CMS). PD-L1 and CD8 expression were examined on a subset of tumors with immunohistochemistry. All statistical tests were two-sided.ResultsThe expression of Immunoscore-like metagenes was statistically significantly associated with improved outcome in non-MSI tumors displaying low levels of both CTLs and immune checkpoints (ICKs; CMS2 and CMS3; hazard ratio [HR] = 0.63, 95% confidence interval [CI] = 0.43 to 0.92, P = .02; and HR = 0.55, 95% CI = 0.34 to 0.90, P = .02, respectively), but clearly had no prognostic relevance in CRCs displaying higher levels of CTLs and ICKs (CMS1 and CMS4; HR = 0.46, 95% CI = 0.10 to 2.10, P = .32; and HR = 1.13, 95% CI = 0.79 to 1.63, P = .50, respectively), including MSI tumors. ICK metagene expression was statistically significantly associated with worse prognosis independent of tumor staging in MSI tumors (HR = 3.46, 95% CI = 1.41 to 8.49, P = .007). ICK expression had a negative impact on the proliferation of infiltrating CD8 T cells in MSI neoplasms (median = 0.56 in ICK low vs median = 0.34 in ICK high, P = .004).ConclusionsICK expression cancels the prognostic relevance of CTLs in highly immunogenic colon tumors and predicts a poor outcome in MSI CRC patients.

Familial breast cancers (BCs) account for 10%-20% of all diagnosed BCs, yet only 20% of such tumors arise in the context of a germline mutation in known tumor suppressor genes such as BRCA1 or BRCA2. The vast genetic heterogeneity which characterizes non BRCA1 and non BRCA2 (or BRCAx) families makes grouped studies impossible to perform. Next generation sequencing techniques, however, allow individual families to be studied to identify rare and or private mutations but the high number of genetic variants identified need to be sorted using pathogenicity or recurrence criteria. An additional sorting criterion may be represented by the identification of candidate regions defined by tumor genomic rearrangements. Indeed, comparative genomic hybridization (CGH) using single nucleotide polymorphism (SNP) arrays allows the detection of conserved ancestral haplotypes within recurrent regions of loss of heterozygosity, common to several familial tumors, which can highlight genomic loci harboring a germline mutation in cancer predisposition genes. The combination of both exome sequencing and SNP array-CGH for a series of familial BC revealed a germline ATM mutation associated with a loss of the wild-type allele in two BC from a BRCAx family. The analysis of additional breast tumors from ten BC families in which a germline ATM mutation had been identified revealed a high frequency of wild-type allele loss. This result argues strongly in favor of the involvement of ATM in these tumors as a tumor suppressor gene and confirms that germline ATM mutations are involved in a subset of familial BC.

The outcome of tumors results from genetic and epigenetic modifications of the transformed cells and also from the interactions of the malignant cells with their tumor microenvironment (TME), which includes immune and inflammatory cells. For a given cancer type, the composition of the immunological TME is not homogeneous. Heterogeneity is found between different cancer types and also between tumors from patients with the same type of cancer. Some tumors exhibit a poor infiltration by immune cells, and others are highly infiltrated by lymphocytes. Among the latter, the architecture of the TME, with the localization of immune cells in the invasive front and the center of the tumor, the presence of tumor-adjacent organized lymphoid aggregates, and the type of inflammatory context, determines the prognostic impact of the infiltrating cells. The description and the understanding of the immune and inflammatory landscape in human tumors are of paramount importance at different levels of patient's care. It completes the mutational, transcriptional, and epigenetic patterns of the malignant cells and open paths to understand how tumor cells shape their immune microenvironment and are shaped by the immune reaction. It provides prognostic and theranostic markers, as well as novel targets for immunotherapies.

Soft tissue sarcomas (STS) form a group of rare cancers which accounts for around 1% of non-pediatric solid tumors. Recent clinical trials with check-point blockade immunotherapies reported a response in up to 15% of patients, but there are no biomarkers predicting response of STS to checkpoint blockade therapies yet. We analyzed transcriptomic data of publicly available cohorts, accounting for more than 600 complex genomic STS, including leiomyosarcoma (LMS, 35.4%), dedifferentiated liposarcoma (DDLPS, 33.9%) and undifferentiated pleomorphic sarcoma (UPS, 30.8%). Using a deconvolution method to estimate the tumor microenvironment composition with accurate scores depicting the immune profile of tumors, we established a robust immune classification that is consistent through different datasets. We divided the patients into 5 Sarcoma Immune Classes, labelled A1, A2, B, C1 and C2, which exhibit different extents and composition of immune infiltrate. Two groups (A1: 23.3% and A2: 27.1% of all tumors) exhibit a very low to low immune infiltrate for all cell types. Another class (B: 14.5% of all tumors) displays moderate immune infiltrate and a strong presence of endothelial cells. Finally, the remaining two groups (C1: 19.4% and C2: 15.6%) are highly infiltrated by all immune cell types. All histologies were found in all five immune classes, although LMS were enriched in classes A1 and A2. The immune-high groups exhibit a significantly prolonged overall survival compared to the other groups. Notably, the immune high group C2 is characterized by an extremely rich immune infiltrate containing both lymphocytes and myeloid cells, and is associated with a striking overexpression of several immune checkpoints genes: PDCD1 (PD-1), CD274 (PD-L1), PDCD1LG2 (PD-L2), LAG3, HAVCR2 (TIM-3), CTLA4. This group also contains tumors with a strong expression of the B cell attractant chemokine CXCL13, often associated with the presence of tertiary lymphoid structures (TLS). We validated the relevance of TLS as a biomarker of this group by quantitative immunohistochemistry (IHC) using stainings for CD3, DC-Lamp, CD8, and CD20 on a 95-patient STS cohort (LMS, 34%; DDLPS, 33%; UPS, 34%). Tumors with visible TLS had a higher density of CD3+, CD8+ and CD20+ cells in the tumor core and the invasive margin, hence showing the possibility to identify the immune-high group by using IHC. The expression of immune checkpoint molecules was also detected by multiplex immunofluorescence for CD3, CD20, PD-1 and Lag3 in these tumors, confirming the presence of checkpoint molecules in the immune-high group. To check whether the immune-high group C2 was associated with enhanced response to checkpoint blockade therapy, we intend to analyze tumors from a recently published phase 2 clinical trial in which patients underwent treatment with anti-PD-1 pembrolizumab. Citation Format: Florent Petitprez, Tom Wei-Wu Chen, Cheng-Ming Sun, Julien Calderaro, Li-Ping Hsiao, Laetitia Lacroix, Ivo Natario, Maud Toulmonde, Carlo Lucchesi, Yec'han Laizet, Antoine Italiano, Aurélien de Reyniès, Catherine Sautès-Fridman, Wolf H. Fridman. A novel transcriptomic-based immune classification of soft tissue sarcoma (STS) and its association with molecular characteristics, clinical outcome and response to therapy [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4045.

Human papillomaviruses (HPV) are associated with a subset of head and neck squamous cell carcinoma (HNSCC), particularly HPV16. This study analyzed the presence and genotype of high risk HPVs, viral DNA load and transcription of the E6/E7 mRNAs, in 231 consecutive HNSCC. Twelve out of 30 HPV16 DNA-positive tumors displayed high E6/E7 mRNAs levels and were localized in the oropharyngeal region. While HPV-free and non-transcriptionally active HPV-related patients showed similar 5-years survival rates, E6/E7 expression was associated with a better prognosis. This emphasizes the importance of considering the transcriptional status of HPV-positive tumors for patient stratification. A gene expression profiling analysis of these different types of tumors was carried out. The most significant differentially expressed gene was CDKN2A, a known biomarker for HPV-related cancer. Assessing both the expression level of the E6/E7 mRNAs and of CDKN2A in HNSCC is required to detect active HPV infection. Chromosomic alterations were investigated by Comparative Genomic Hybridation (CGH) analysis of tumors with transcriptionally active HPV and HPV-negative tumors. The loss of the chromosomal region 16q was found to be a major genetic event in HPV-positive lesions. A cluster of genes located in 16q21-24 displayed decreased expression levels, notably APP-BP1 that is involved in the modulation of the transcriptional activity of p53. In conclusion, this study highlights important criteria required to predict clinically active HPV infection, identifies new biological pathways implicated in HPV tumorigenesis and increases the understanding of HPV-HNSCC physiopathology that is required to develop new targets for therapy.

Hepatocellular carcinomas (HCCs) are a heterogeneous group of tumors that differ in risk factors and genetic alterations. We further investigated transcriptome-genotype-phenotype correlations in HCC. Global transcriptome analyses were performed on 57 HCCs and 3 hepatocellular adenomas and validated by quantitative RT-PCR using 63 additional HCCs. We determined loss of heterozygosity, gene mutations, promoter methylation of CDH1 and CDKN2A, and HBV DNA copy number for each tumor. Unsupervised transcriptome analysis identified 6 robust subgroups of HCC (G1-G6) associated with clinical and genetic characteristics. G1 tumors were associated with low copy number of HBV and overexpression of genes expressed in fetal liver and controlled by parental imprinting. G2 included HCCs infected with a high copy number of HBV and mutations in PIK3CA and TP53. In these first groups, we detected specific activation of the AKT pathway. G3 tumors were typified by mutation of TP53 and overexpression of genes controlling the cell cycle. G4 was a heterogeneous subgroup of tumors including TCF1-mutated hepatocellular adenomas and carcinomas. G5 and G6 were strongly related to beta-catenin mutations that lead to Wnt pathway activation; in particular, G6 tumors were characterized by satellite nodules, higher activation of the Wnt pathway, and E-cadherin underexpression. CONCLUSION: These results have furthered our understanding of the genetic diversity of human HCC and have provided specific identifiers for classifying tumors. In addition, our classification has potential therapeutic implications because 50% of the tumors were related to WNT or AKT pathway activation, which potentially could be targeted by specific inhibiting therapies.

Purpose: The tumor microenvironment is formed by many distinct and interacting cell populations, and its composition may predict patients' prognosis and response to therapies. Colorectal cancer is a heterogeneous disease in which immune classifications and four consensus molecular subgroups (CMS) have been described. Our aim was to integrate the composition of the tumor microenvironment with the consensus molecular classification of colorectal cancer. Experimental Design: We retrospectively analyzed the composition and the functional orientation of the immune, fibroblastic, and angiogenic microenvironment of 1,388 colorectal cancer tumors from three independent cohorts using transcriptomics. We validated our findings using immunohistochemistry. Results: We report that colorectal cancer molecular subgroups and microenvironmental signatures are highly correlated. Out of the four molecular subgroups, two highly express immune-specific genes. The good-prognosis microsatellite instable–enriched subgroup (CMS1) is characterized by overexpression of genes specific to cytotoxic lymphocytes. In contrast, the poor-prognosis mesenchymal subgroup (CMS4) expresses markers of lymphocytes and of cells of monocytic origin. The mesenchymal subgroup also displays an angiogenic, inflammatory, and immunosuppressive signature, a coordinated pattern that we also found in breast (n = 254), ovarian (n = 97), lung (n = 80), and kidney (n = 143) cancers. Pathologic examination revealed that the mesenchymal subtype is characterized by a high density of fibroblasts that likely produce the chemokines and cytokines that favor tumor-associated inflammation and support angiogenesis, resulting in a poor prognosis. In contrast, the canonical (CMS2) and metabolic (CMS3) subtypes with intermediate prognosis exhibit low immune and inflammatory signatures. Conclusions: The distinct immune orientations of the colorectal cancer molecular subtypes pave the way for tailored immunotherapies. Clin Cancer Res; 22(16); 4057–66. ©2016 AACR.

Purpose: Selecting patients with metastatic clear-cell renal cell carcinoma (m-ccRCC) who might benefit from treatment with targeted tyrosine kinase inhibitors (TKI) is a challenge. Our aim was to identify molecular markers associated with outcome in patients with m-ccRCC treated with sunitinib. Experimental Design: We performed global transcriptome analyses on 53 primary resected ccRCC tumors from patients who developed metastatic disease and were treated with first-line sunitinib. We also determined chromosome copy-number aberrations, methylation status, and gene mutations in von Hippel–Lindau and PBRM1. Molecular data were analyzed in relation with response rate (RR), progression-free survival (PFS), and overall survival (OS). Validation was performed in 47 additional ccRCC samples treated in first-line metastatic setting with sunitinib. Results: Unsupervised transcriptome analysis identified 4 robust ccRCC subtypes (ccrcc1 to 4) related to previous molecular classifications that were associated with different responses to sunitinib treatment. ccrcc1/ccrcc4 tumors had a lower RR (P = 0.005) and a shorter PFS and OS than ccrcc2/ccrcc3 tumors (P = 0.001 and 0.0003, respectively). These subtypes were the only significant covariate in the multivariate Cox model for PFS and OS (P = 0.017 and 0.006, respectively). ccrcc1/ccrcc4 tumors were characterized by a stem-cell polycomb signature and CpG hypermethylation, whereas ccrcc3 tumors, sensitive to sunitinib, did not exhibit cellular response to hypoxia. Moreover, ccrcc4 tumors exhibited sarcomatoid differentiation with a strong inflammatory, Th1-oriented but suppressive immune microenvironment, with high expression of PDCD1 (PD-1) and its ligands. Conclusions: ccRCC molecular subtypes are predictive of sunitinib response in metastatic patients, and could be used for personalized mRCC treatment with TKIs, demethylating or immunomodulatory drugs. Clin Cancer Res; 21(6); 1329–39. ©2015 AACR.

3509 Background: The molecular subtyping of colon cancers (CC) has been the subject of several recent publications, leading to an international consensus. The clinical relevance of these molecular classifications remains to be evaluated on large prospective patient cohorts using a tool that can be widely used on formalin-fixed paraffin-embedded (FFPE) samples. Methods: We aimed to evaluate the clinical relevance of two molecular subtyping systems, CMS (Guinney et al. 2015) and CCMST (Marisa et al. 2013), on the PETACC-8 cohort, a randomized phase III trial comparing adjuvant FOLFOX with or without cetuximab in patients with stage III CC. For each of these two classification systems, a predictor tool was developed and adapted to FFPE samples. The NanoString nCounter platform was used to screen 196 genes. Predictors were built from 249 frozen tumor samples previously used to build our classification system and 61 new paired FFPE/frozen samples. Both predictors were then applied to 1781 PETACC-8 FFPE samples. Subtypes associations to clinical and molecular features were analyzed. Results: The CMS predictor assigned 297 samples to CMS1 (17%), 585 to CMS2 (34%), 68 to CMS3 (4%) and 770 to CMS4 (45%). CMS were significantly associated with several molecular and clinical features, including MSI status (49% in CMS1, p < 0.001), CIMP status (47% in CMS1, p < 0.001), KRAS mutation (75% in CMS3, p < 0.001), BRAF mutation (34% in CMS1, p < 0.001), tumor location (less proximal tumors in CMS2, p < 0.001), validating the predictor tool developed. The classification was significantly associated to prognosis in multivariate analysis, CMS4 subtype having a shorter overall survival (hazard ratio = 1.7, p= 0.021). A deleterious effect of cetuximab was observed in CMS1 (p < 0.05). Similar results were obtained with the CCMST classification. Conclusions: We validated molecular CC subtyping predictors for both CMS and CCMST classifications on PETACC-8 FFPE samples. The prognostic value of CMS and CCMST classifications was confirmed, stem-like tumors being associated with a poor prognosis. These results pave the avenue for widely use of the CC molecular classification in clinical routine.

International audience; Adrenocortical carcinomas (ACCs) are aggressive cancers originating in the cortex of the adrenal gland. Despite overall poor prognosis, ACC outcome is heterogeneous. We performed exome sequencing and SNP array analysis of 45 ACCs and identified recurrent alterations in known driver genes (CTNNB1, TP53, CDKN2A, RB1 and MEN1) and in genes not previously reported in ACC (ZNRF3, DAXX, TERT and MED12), which we validated in an independent cohort of 77 ACCs. ZNRF3, encoding a cell surface E3 ubiquitin ligase, was the most frequently altered gene (21%) and is a potential new tumor suppressor gene related to the β-catenin pathway. Our integrated genomic analyses further identified two distinct molecular subgroups with opposite outcome. The C1A group of ACCs with poor outcome displayed numerous mutations and DNA methylation alterations, whereas the C1B group of ACCs with good prognosis displayed specific deregulation of two microRNA clusters. Thus, aggressive and indolent ACCs correspond to two distinct molecular entities driven by different oncogenic alterations.

Purpose: Despite research efforts to develop more effective diagnostic and therapeutic approaches, malignant pleural mesothelioma (MPM) prognosis remains poor. The assessment of tumor response to therapy can be improved by a deeper phenotypical classification of the tumor, with emphasis on its clinico-biological heterogeneity. The identification of molecular profiles is a powerful approach to better define MPM subclasses and targeted therapies. Experimental Design: Molecular subclasses were defined by transcriptomic microarray on 38 primary MPM cultures. A three-gene predictor, identified by quantitative reverse transcription PCR, was used to classify an independent series of 108 frozen tumor samples. Gene mutations were determined in BAP1, CDKN2A, CDKN2B, NF2, and TP53. Epithelial-to-mesenchymal transition (EMT) markers were studied at the mRNA and protein levels. Results: Unsupervised hierarchical clustering on transcriptomic data defined two robust MPM subgroups (C1 and C2), closely related to prognosis and partly to histologic subtypes. All sarcomatoid/desmoplastic MPM were included in the C2 subgroup. Epithelioid MPM were found in both subgroups, with a worse survival prognosis in the C2 subgroup. This classification and its association with histologic subtypes and survival were validated in our independent series using the three-gene predictor. Similar subgroups were found after classification of other MPM series from transcriptomic public datasets. C1 subgroup exhibited more frequent BAP1 alterations. Pathway analysis revealed that EMT was differentially regulated between MPM subgroups. C2 subgroup is characterized by a mesenchymal phenotype. Conclusions: A robust classification of MPM that defines two subgroups of epithelioid MPM, characterized by different molecular profiles, gene alterations, and survival outcomes, was established. Clin Cancer Res; 20(5); 1323–34. ©2014 AACR.

International audience; Angioimmunoblastic T-cell Lymphoma (AITL) is one of the most frequent T-cell lymphoma entities. Follicular helper T lymphocytes (TFH) are recognized as the normal cellular counterpart of the neoplastic component. Despite a clonal T-cell feature and few described recurrent cytogenetic abnormalities, a driving oncogenic event has not been identified so far. It has been recently reported that in mice, heterozygous inactivation of Roquin/Rc3h1, a RING type E3 ubiquitine ligase, recapitulates many of the clinical, histological, and cellular features associated with human AITL. In this study we explored whether ROQUIN alterations could be an initial event in the human AITL oncogenic process. Using microarray and RT-PCR analyses, we investigated the levels of ROQUIN transcripts in TFH tumor cells purified from AITL (n = 8) and reactive tonsils (n = 12) and found similar levels of ROQUIN expression in both. Moreover, we also demonstrated that ROQUIN protein was expressed by AITL TFH (PD1+) cells. We then analysed ROQUIN coding sequence in 12 tumor cell-rich AITL samples and found no mutation in any of the samples. Finally, we analysed the expression of MiR101, a putative partner of ROQUIN involved in the modulation of ICOS expression and found similar levels of expression in tumor and reactive TFH. Altogether, this study shows that neither alteration of ROQUIN gene nor deregulation of miR101 expression is likely to be a frequent recurrent event in AITL.

Background Despite entering complete remission after primary treatment, a substantial proportion of patients with early stage breast cancer will develop metastases. Prediction of such an outcome remains challenging despite the clinical use of several prognostic parameters. Several reports indicate that genomic instability, as reflected in specific chromosomal aneuploidies and variations in DNA content, influences clinical outcome but no precise definition of this parameter has yet been clearly established. Methods To explore the prognostic value of genomic alterations present in primary tumors, we performed a comparative genomic hybridization study on BAC arrays with a panel of breast carcinomas from 45 patients with metastatic relapse and 95 others, matched for age and axillary node involvement, without any recurrence after at least 11 years of follow-up. Array-CGH data was used to establish a two-parameter index representative of the global level of aneusomy by chromosomal arm, and of the number of breakpoints throughout the genome. Results Application of appropriate thresholds allowed us to distinguish three classes of tumors highly associated with metastatic relapse. This index used with the same thresholds on a published set of tumors confirms its prognostic significance with a hazard ratio of 3.24 [95CI: 1.76-5.96] p = 6.7x10-5 for the bad prognostic group with respect to the intermediate group. The high prognostic value of this genomic index is related to its ability to individualize a specific group of breast cancers, mainly luminal type and axillary node negative, showing very high genetic instability and poor outcome. Indirect transcriptomic validation was obtained on independent data sets. Conclusion Accurate evaluation of genetic instability in breast cancers by a genomic instability index (G2I) helps individualizing specific tumors with previously unexpected very poor prognosis.

International audience; Dense genotype data can be used to detect chromosome fragments inherited from a common ancestor in apparently unrelated individuals. A disease-causing mutation inherited from a common founder may thus be detected by searching for a common haplotype signature in a sample population of patients. We present here FounderTracker, a computational method for the genome-wide detection of founder mutations in cancer using dense tumor SNP profiles. Our method is based on two assumptions. First, the wild-type allele frequently undergoes loss of heterozygosity (LOH) in the tumors of germline mutation carriers. Second, the overlap between the ancestral chromosome fragments inherited from a common founder will define a minimal haplotype conserved in each patient carrying the founder mutation. Our approach thus relies on the detection of haplotypes with significant identity by descent (IBD) sharing within recurrent regions of LOH to highlight genomic loci likely to harbor a founder mutation. We validated this approach by analyzing two real cancer data sets in which we successfully identified founder mutations of well-characterized tumor suppressor genes. We then used simulated data to evaluate the ability of our method to detect IBD tracts as a function of their size and frequency. We show that FounderTracker can detect haplotypes of low prevalence with high power and specificity, significantly outperforming existing methods. FounderTracker is thus a powerful tool for discovering unknown founder mutations that may explain part of the "missing" heritability in cancer. This method is freely available and can be used online at the FounderTracker website.

The pathogenesis of hepatosplenic T-cell lymphoma (HSTL), a rare entity mostly derived from γδ T cells and usually with a fatal outcome, remains largely unknown. In this study, HSTL samples (7γδ and 2αβ) and the DERL2 HSTL cell line were subjected to combined gene-expression profiling and array-based comparative genomic hybridization. Compared with other T-cell lymphomas, HSTL had a distinct molecular signature irrespective of TCR cell lineage. Compared with peripheral T-cell lymphoma, not otherwise specified and normal γδ T cells, HSTL overexpressed genes encoding NK-cell–associated molecules, oncogenes (FOS and VAV3), the sphingosine-1-phosphatase receptor 5 involved in cell trafficking, and the tyrosine kinase SYK, whereas the tumor-suppressor gene AIM1 (absent in melanoma 1) was among the most down-expressed. We found highly methylated CpG islands of AIM1 in DERL2 cells, and decitabine treatment induced a significant increase in AIM1 transcripts. Syk was present in HSTL cells and DERL2 cells contained phosphorylated Syk and were sensitive to a Syk inhibitor in vitro. Genomic profiles confirmed recurrent isochromosome 7q (n = 6/9) without alterations at the SYK and AIM1 loci. Our results identify a distinct molecular signature for HSTL and highlight oncogenic pathways that offer rationale for exploring new therapeutic options such as Syk inhibitors and demethylating agents.

Diagnosing malignancy of adrenocortical tumors (ACT) and predicting prognosis in carcinomas are often challenging. Transcriptome markers have recently emerged, providing promising clinical relevance and improved pathophysiological knowledge. Whether tumoral chromosomal alterations provide similar information is not known. The aim was to evaluate the diagnostic and prognostic value of chromosomal alterations in ACT and to identify genes associated with benign and malignant tumorigenesis.Chromosomal alterations of 86 adenomas and 52 carcinomas were identified by comparative genomic hybridization arrays and/or quantitative PCR.A larger proportion of the genome is altered in carcinomas compared with adenomas (44 vs. 10%, P = 2.10(-10)). In adenomas, the 9q34 region, which includes the steroidogenic factor 1 locus, is commonly gained and associated with an overexpression of steroidogenic factor 1 (SF-1). In carcinomas, recurrent gains include chromosomes 5, 7, 12, 16, 19, and 20 and recurrent losses chromosomes 13 and 22. Filtering the genes from these regions according to their expression profile identified genes potentially relevant to adrenocortical tumorigenesis. A diagnostic tool was built by combining DNA copy number estimates at six loci (5q, 7p, 11p, 13q, 16q, and 22q). This tool discriminates carcinomas from adenomas in an independent validation cohort (sensitivity 100%, specificity 83%). In carcinomas, the number of chromosomal alterations was not associated with survival (Cox P = 0.84). A prognostic tool based on tumor DNA was designed with a clustering strategy and validated in an independent cohort.Chromosomal alterations in ACT discriminate carcinomas from adenomas and contain prognostic information. Chromosomal alterations alter the expression of genes important for tumorigenesis.

International audience; Malignant mesothelioma (MM) is an aggressive tumor with a poor prognosis mainly linked to past asbestos exposure. Murine models of MM based on fiber exposure have been developed to elucidate the mechanism of mesothelioma formation. Genomic alterations in murine MM have now been partially characterized. To gain insight into the pathophysiology of mesothelioma, 16 murine and 35 human mesotheliomas were characterized by array-comparative genomic hybridization and were screened for common genomic alterations. Alteration of the 9p21 human region, often by biallelic deletion, was the most frequent alteration in both species, in agreement with the CDKN2A/CDKN2B locus deletion in human disease and murine models. Other shared aberrations were losses of 1p36.3-p35 and 13q14-q33 and gains of 5p15.3-p13 regions. However, some differences were noted, such as absence of recurrent alterations in mouse regions corresponding to human chromosome 22. Comparison between altered recurrent regions in asbestos-exposed and non-asbestos-exposed patients showed a significant difference in the 14q11.2-q21 region, which was also lost in fiber-induced murine mesothelioma. A correlation was also demonstrated between genomic instability and tumorigenicity of human mesothelioma xenografts in nude mice. Overall, these data show similarities between murine and human disease, and contribute to the understanding of the influence of fibers in the pathogenesis of mesothelioma and validation of the murine model for preclinical testing.