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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.

XLS file - 11306KB, Pathway analysis.

XLS file - 212KB, Sample annotations and gene expression.

PDF file - 58KB, Primer sequences used for BAP1 and CDKN2B gene analysis.

PDF file - 356KB, This file contains supplementary figures S1-S7. Figure S1: Flowchart depicting the analyses carried out to establish and validate a molecular classification of MPM; Figure S2: Unsupervised molecular subgroups in the discovery series; Figures S3: Recurrent regions of chromosomal alteration in MPM molecular subgroups; Figures S4: Identification of the three-gene predictor; Figure S5: Unsupervised molecular subgroups in the two public series; Figure S6: Distribution of histological subtypes and overall survival differences between MPM molecular subgroups in the two public series; Figure S7: Differential mRNA expression of epithelial-to-mesenchymal transition (EMT) markers in MPM molecular subgroups.

XLS file 669K, This file contains supplementary table S4: Convergence between microRNA and mRNA deregulation

Legends of Supplementary Figures and Tables PDF file 134K, This file contains the legends for supplementary figures S1-S7 and tables S1-S4

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.

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.

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.

The chromosome translocations generating PAX3FOXO1 and PAX7FOXO1 chimeric proteins are the primary hallmarks of the paediatric cancer, Alveolar Rhabdomyosarcoma (ARMS). Despite the ability of these transcription factors to remodel chromatin landscapes and promote the expression of tumour driver genes, they only inefficiently promote malignant transformationin vivo. The reason for this is unclear. To address this, we developed anin ovomodel to follow the response of spinal cord progenitors to PAXFOXO1s. Our data demonstrate that PAXFOXO1s, but not wild-type PAX3 and PAX7, trigger the trans-differentiation of neural cells into ARMS-like cells with myogenic characteristics. In parallel expression of PAXFOXO1s remodels the neural pseudo-stratified epithelium into a cohesive mesenchyme capable of tissue invasion. Surprisingly, gain for PAXFOXO1s, as for wild-type PAX3/7, reduces the levels of CDK-CYCLIN activity and arrests cells in G1. Introduction of CYCLIN D1 or MYCN overcomes PAXFOXO1s mediated cell cycle inhibition and promotes tumour growth. Together, our findings reveal a mechanism underpinning the apparent limited oncogenicity of PAXFOXO1 fusion transcription factors and support a neural origin for ARMS.

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.

Background 1p/19q-codeleted anaplastic gliomas have variable clinical behavior. We have recently shown that the common 9p21.3 allelic loss is an independent prognostic factor in this tumor type. The aim of this study is to identify less frequent genomic copy number variations (CNVs) with clinical importance that may shed light on molecular oncogenesis of this tumor type. Materials and Methods A cohort of 197 patients with anaplastic oligodendroglioma was collected as part of the French POLA network. Clinical, pathological, and molecular information was recorded. CNV analysis was performed using single-nucleotide polymorphism arrays. Computational biology and feature selection based on the random forests method were used to identify CNV events associated with overall survival and other clinical-pathological variables. Results Recurrent chromosomal events were identified in chromosomes 4, 9, and 11. Forty-six focal amplification events and 22 focal deletion events were identified. Twenty-four focal CNV areas were associated with survival, and five of them were significantly associated with survival after multivariable analysis. Nine out of 24 CNV events were validated using an external cohort of The Cancer Genome Atlas. Five of the validated events contain a cancer-related gene or microRNA: CDKN2A deletion, SS18L1 amplification, RHOA/MIR191 copy-neutral loss of heterozygosity, FGFR3 amplification, and ARNT amplification. The CNV profile contributes to better survival prediction compared with clinical-based risk assessment. Conclusion Several recurrent CNV events, detected in anaplastic oligodendroglioma, enable better survival prediction. More importantly, they help in identifying potential genes for understanding oncogenesis and for personalized therapy. Implications for Practice Genomic analysis of 197 anaplastic oligodendroglioma tumors reveals recurrent somatic copy number variation areas that may help in understanding oncogenesis and target identification for precision medicine. A machine learning multivariable model built using this genomic information enables better survival prediction.

Recent studies have offered ample insight into genome-wide expression patterns to define pancreatic ductal adenocarcinoma (PDAC) subtypes, although there remains a lack of knowledge regarding the underlying epigenomics of PDAC. Here we perform multi-parametric integrative analyses of chromatin immunoprecipitation-sequencing (ChIP-seq) on multiple histone modifications, RNA-sequencing (RNA-seq), and DNA methylation to define epigenomic landscapes for PDAC subtypes, which can predict their relative aggressiveness and survival. Moreover, we describe the state of promoters, enhancers, super-enhancers, euchromatic, and heterochromatic regions for each subtype. Further analyses indicate that the distinct epigenomic landscapes are regulated by different membrane-to-nucleus pathways. Inactivation of a basal-specific super-enhancer associated pathway reveals the existence of plasticity between subtypes. Thus, our study provides new insight into the epigenetic landscapes associated with the heterogeneity of PDAC, thereby increasing our mechanistic understanding of this disease, as well as offering potential new markers and therapeutic targets., Pancreatic ductal adenocarcinoma (PDAC) is a complex disease and its underlying epigenomic heterogeneity is not fully understood. Here, the authors utilize patient-derived PDAC xenografts to define the epigenomic landscape of PDAC, highlighting chromatin states linked to differing disease aggressiveness and survival.

Background & Aims Recent studies have shown that cancers arise as a result of the positive selection of driver somatic events in tumor DNA, with negative selection playing only a minor role, if any. However, these investigations were concerned with alterations at nonrepetitive sequences and did not take into account mutations in repetitive sequences that have very high pathophysiological relevance in the tumors showing microsatellite instability (MSI) resulting from mismatch repair deficiency investigated in the present study. Methods We performed whole-exome sequencing of 47 MSI colorectal cancers (CRCs) and confirmed results in an independent cohort of 53 MSI CRCs. We used a probabilistic model of mutational events within microsatellites, while adapting pre-existing models to analyze nonrepetitive DNA sequences. Negatively selected coding alterations in MSI CRCs were investigated for their functional and clinical impact in CRC cell lines and in a third cohort of 164 MSI CRC patients. Results Both positive and negative selection of somatic mutations in DNA repeats was observed, leading us to identify the expected true driver genes associated with the MSI-driven tumorigenic process. Several coding negatively selected MSI-related mutational events (n = 5) were shown to have deleterious effects on tumor cells. In the tumors in which deleterious MSI mutations were observed despite the negative selection, they were associated with worse survival in MSI CRC patients (hazard ratio, 3; 95% CI, 1.1–7.9; P = .03), suggesting their anticancer impact should be offset by other as yet unknown oncogenic processes that contribute to a poor prognosis. Conclusions The present results identify the positive and negative driver somatic mutations acting in MSI-driven tumorigenesis, suggesting that genomic instability in MSI CRC plays a dual role in achieving tumor cell transformation. Exome sequencing data have been deposited in the European genome–phenome archive (accession: EGAS00001002477)., Graphical abstract

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.

Malignant pleural mesothelioma (MPM) is recognized as heterogeneous based both on histology and molecular profiling. Histology addresses inter-tumor and intra-tumor heterogeneity in MPM and describes three major types: epithelioid, sarcomatoid and biphasic, a combination of the former two types. Molecular profiling studies have not addressed intra-tumor heterogeneity in MPM to date. Here, we use a deconvolution approach and show that molecular gradients shed new light on the intra-tumor heterogeneity of MPM, leading to a reconsideration of MPM molecular classifications. We show that each tumor can be decomposed as a combination of epithelioid-like and sarcomatoid-like components whose proportions are highly associated with the prognosis. Moreover, we show that this more subtle way of characterizing MPM heterogeneity provides a better understanding of the underlying oncogenic pathways and the related epigenetic regulation and immune and stromal contexts. We discuss the implications of these findings for guiding therapeutic strategies, particularly immunotherapies and targeted therapies., Malignant pleural mesothelioma (MPM) is a rare and aggressive form of cancer. Here, the authors show MPM is heterogeneously composed of epithelioid and sarcomatoid components and their proportions associate with prognosis and could inform therapeutic strategies.

Oligodendroglial tumours (OT) are a heterogeneous group of gliomas. Three molecular subgroups are currently distinguished on the basis of the IDH mutation and 1p/19q co-deletion. Here we present an integrated analysis of the transcriptome, genome and methylome of 156 OT. Not only does our multi-omics classification match the current classification but also reveals three subgroups within 1p/19q co-deleted tumours, associated with specific expression patterns of nervous system cell types: oligodendrocyte, oligodendrocyte precursor cell (OPC) and neuronal lineage. We confirm the validity of these three subgroups using public datasets. Importantly, the OPC-like group is associated with more aggressive clinical and molecular patterns, including MYC activation. We show that the MYC activation occurs through various alterations, including MYC genomic gain, MAX genomic loss, MYC hypomethylation and microRNA-34b/c down-regulation. In the lower grade glioma TCGA dataset, the OPC-like group is associated with a poorer outcome independently of histological grade. Our study reveals previously unrecognized heterogeneity among 1p/19q co-deleted tumours., Oligodendroglial tumours are characterized into three different molecular subtypes. Here, the authors use genomic data to identify a further three subgroups of 1p/19q co-deleted tumours and demonstrate an association with an aggressive phenotype.

Background Management of localized prostate cancer (PCa) is a major clinical challenge since most of these cancers would not evolve but a majority of patients will still undergo a life-changing radical surgery. Molecular studies have shown that PCa can be classified according to their genomic alterations but none of the published PCa molecular classifications could identify a subtype corresponding to non-evolutive tumours. Materials and methods Multi-omics molecular profiling was carried out on post-radical prostatectomy material from a cohort of 130 patients with localized PCa. We used unsupervised classification techniques to build a comprehensive classification of prostate tumours based on three molecular levels: DNA copy number, DNA methylation, and mRNA expression. Merged data from our cohort and The Cancer Genome Atlas cohort were used to characterize the resulting tumour subtypes. We measured subtype-associated risks of biochemical relapse using Cox regression models and survival data from five cohorts including the two aforementioned. Results We describe three PCa molecular subtypes associated with specific molecular characteristics and different clinical outcomes. Particularly, one subtype was strongly associated with the absence of biochemical recurrence. We validated this finding on 746 samples from 5 distinct cohorts (P = 3.41 × 10−8, N = 746 tumour samples), and showed that our subtyping approach outperformed the most popular prognostic molecular signatures to accurately identify a subset of patients with a non-evolutive disease. We provide a set of 36 transcriptomic biomarkers to robustly identify this subtype of non-evolutive cases whose prevalence was estimated to 22% of all localized PCa tumours. Conclusion At least 20% of patients with localized PCa can be accurately predicted to have a non-evolutive disease on the basis of their molecular subtype. Those patients should not undergo immediate surgery and rather be placed under active surveillance.

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 Tumor pathologists classify tumors according to cell-level and tissue-level criteria, using molecular markers in addition to morphological patterns, as reported in WHO tumor classifications. Their work describes to some extent both inter-tumor and intra-tumor heterogeneity, but it is a tedious task with potential reproducibility issues. The molecular subtyping of tumors represents a sometimes parallel and sometimes convergent effort to describe the heterogeneity of tumors. It is automated, which attenuates the limitations of pathological scoring mentioned above, but so far it is poorly adapted to describe intra-tumor heterogeneity. Methods We propose a novel method, WISP (Weighted In Silico Pathology), which finely measures intra-tumor heterogeneity by automatically estimating the proportions of cell types present in a bulk tumor sample, these cell types being predefined based on histological or high-throughput molecular criterions. Results We illustrate the relevance of our approach in several tumor types including lung cancer, glioblastoma and pancreatic cancer. We show that the cell types that describe tumors for a given cancer type can fairly well recapitulate existing molecular classifications and are very consistent with an independent pathological scoring. We show that our method offers a more standardized and finer-grained solution for describing tumor heterogeneity than either pathological scoring or molecular subtyping. More importantly, we show that the proportion of certain cell types is strongly associated to prognosis and drug response. Conclusions This study provides a framework for standardized molecular pathology and fully reshapes the way in which we think about pathology or molecular subtyping. We believe that our results are a proof of concept demonstrating the importance of considering cell types intra-tumor proportions for personalized clinical care. Legal entity responsible for the study The authors. Funding CIT Program - Ligue Contre le Cancer. Disclosure All authors have declared no conflicts of interest.

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.

BACKGROUND: Although major advances have been accomplished over the last years in their characterization, 1p/19q-codeleted anaplastic gliomas have variable clinical behavior and mysterious 1p/19q-codeletion “driven” molecular oncogenesis. We have recently shown that the most common alteration (i.e. 9p21.3 allelic loss detected in 42% of cases) is an independent prognostic factor in this tumor type. However, less frequent Genomic Copy Number Variations (CNV) may also have clinical value and may shed light on molecular oncogenesis of this tumor type. METHODS: A cohort of 197, 1p/19q-codeleted grade III gliomas was collected as part of the French POLA network. Clinical, pathological and molecular information were recorded and the patients were clinically followed up. CNV analysis was performed using SNP arrays. Computational biology and machine learning analysis were applied to identify less common additional CNV events associated with overall survival and other clinical-pathological variables Results: Recurrent chromosomal events were identified in chromosomes 4, 9, and 11. 46 focal amplification events and 22 focal deletion events were identified. 12 of the focal events overlapped with known cancer related genomic regions. 24 focal CNV areas were associated with survival and five of them were significantly associated with survival after multivariate analysis. 9/24 signals, detected in 3 to 26 percent of patients, were validated using an external cohort of gliomas of the Cancer Genome Atlas. Five of the validated signals contain a cancer related gene or MIR: CDKN2A deletion, SS18L1 amplification, RHOA/MIR191 copy-neutral loss of heterozigosity, FGFR3 amplification, and ARNT amplification. The CNV profile enables better survival prediction compared to clinical risk assessment. Conclusions: Several recurrent CNV events are characteristics for 1p/19q-codeleted grade III gliomas. These genomic regions are associated with survival and enable better survival prediction. More important, they may help identifying potential genes for understanding oncogenesis and for personalized therapy.

New molecular pathways involved in alveolar rhabdomyosarcoma aggressiveness are found by identifying the RhoE/ROCK/ARHGAP25 signaling pathway as promoting the invasive potential of alveolar rhabdomyosarcoma., Rhabdomyosarcoma (RMS) is the most common soft tissue sarcoma of skeletal muscle origin in children and adolescents. Among RMS subtypes, alveolar rhabdomyosarcoma (ARMS), which is characterized by the presence of the PAX3-FOXO1A or PAX7-FOXO1A chimeric oncogenic transcription factor, is associated with poor prognosis and a strong risk of metastasis compared with the embryonal subtype (ERMS). To identify molecular pathways involved in ARMS aggressiveness, we first characterized the migratory behavior of cell lines derived from ARMS and ERMS biopsies using a three-dimensional spheroid cell invasion assay. ARMS cells were more invasive than ERMS cells and adopted an ellipsoidal morphology to efficiently invade the extracellular matrix. Moreover, the invasive potential of ARMS cells depended on ROCK activity, which is regulated by the GTPase RhoE. Specifically, RhoE expression was low in ARMS biopsies, and its overexpression in ARMS cells reduced their invasion potential. Conversely, ARHGAP25, a GTPase-activating protein for Rac, was up-regulated in ARMS biopsies. Moreover, we found that ARHGAP25 inhibits Rac activity downstream of ROCKII and is required for ARMS cell invasion. Our results indicate that the RhoE/ROCK/ARHGAP25 signaling pathway promotes ARMS invasive potential and identify these proteins as potential therapeutic targets for ARMS treatment.

Introduction: Pancreatic ductal adenocarcinoma (PDA) carries a dismal prognosis. Virtually all PDA are characterized by mutation of four driver genes: KRAS, TP53, CDKN2A and SMAD4 and a long tail of rarely mutated genes. Application of targeted next-generation sequencing (NGS) has entered clinical routine for colon, lung and other cancers. Among patients with resected PDA, usefulness, applicability and prognostic significance of NGS results are still a matter of debate. Aims: To evaluate: 1) the alterations of the 4 main driver genes and patient outcomes after resection 2) the usefulness of targeted NGS in finding targetable alterations. Methods: We analyzed DNA alterations in FFPE tumors among 279 patients with curatively resected PDA who were treated at 4 Academic Hospitals (Franco-Belgian consortium). Sequencing libraries were prepared using a 50 genes panel (Ion AmpliSeqTM Cancer HotSpot Panel v2, Life Technologies). Sequencing was performed on an Ion ProtonTM System using an Ion PITM Sequencing 200 Kit and an Ion PITM Chip Kit v3 (Life Technologies). Associations of driver gene alterations with disease-free survival (DFS) and overall survival (OS) were evaluated using Cox proportional hazards regression with estimation of hazard ratios (HRs) and 95% CIs and adjusted for age, sex, tumor characteristics and institution. Results: Of the 279 patients analyzed, 163 (58.4%) were men and 116 (41.6%) were women, with a median age of 64.59 (36.9-87.5) years. KRAS, TP53, CDKN2A and SMAD 4 were mutated in 246, 193, 45 and 44 patients respectively. Patients with KRAS mutant tumors did not have worse DFS (median [95% CI], 12.2 [11.35-14.6] months) and OS (23.9 [21.1-30.1] months) compared to patients with KRAS wild-type tumors (DFS, 14.3 [9.64-19.4] months; OS, 31.8 [19.4-53.5] months). The mutational status of TP53 or SMAD4 was not associated with DFS or OS as well. CDKN2A mutations were associated with a lower OS (mutation: 20.5 [14.6-33.0] versus wild-type 26.5 [21.9-33.3] months OS, log-rank Citation Format: Francesco Puleo, Rémy Nicolle, Yuna Blum, Jérôme Cros, Nabila Elarouci, Denis Franchimont, Jacques Devière, Aurélien de Reyniès, Pierre Laurent-Puig, Jean-Baptiste Bachet, Raphaël Maréchal, Jean-Luc Van Laethem. Clinical application and potential usefulness of targeted next-generation sequencing on resected pancreatic ductal adenocarcinoma [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 4603.

Developmental genes contribute to cancer, as reported for the homeobox gene Cdx2 playing a tumor suppressor role in the gut. In this study, we show that human colon cancers exhibiting the highest reduction in CDX2 expression belong to the serrated subtype with the worst evolution. In mice, mosaic knockout of Cdx2 in the adult intestinal epithelium induces the formation of imperfect gastric-type metaplastic lesions. The metaplastic knockout cells do not spontaneously become tumorigenic. However, they induce profound modifications of the microenvironment that facilitate the tumorigenic evolution of adjacent Cdx2-intact tumor-prone cells at the surface of the lesions through NF-κB activation, induction of inducible nitric oxide synthase, and stochastic loss of function of Apc. This study presents a novel paradigm in that metaplastic cells, generally considered as precancerous, can induce tumorigenesis from neighboring nonmetaplastic cells without themselves becoming cancerous. It unveils the novel property of non–cell-autonomous tumor suppressor gene for the Cdx2 gene in the gut.

Patient-derived xenografts (PDX) are appearing as a prime approach for preclinical studies despite being insufficiently characterized as a model of the human disease and its diversity. In this work, 29 PDX were obtained from either surgery or endoscopic ultrasound-guided fine needle aspirate of pancreatic adenocarcinoma. The extensive genomic profiling of these pancreatic PDX, revealed two clinically-relevant subtypes having broad similarities with human primary tumors. These subtypes are defined by highly specific DNA methylation and transcriptomic profiles (mRNA, miRNA or lncRNA) but are not distinguishable by exonic mutations or copy number aberrations. Moreover, by specifically analyzing the stroma transcriptome, as defined by the expression of murine transcripts, we found that it is able to stratify the patients with the same efficiency than the analysis of grafted human tumor cells. This finding suggest that transformed pancreatic cells drive the composition of their own stroma. Finally, the multiomics analysis pinpoints novel therapeutic targets, one of which we demonstrate to be an efficient method for treating pancreatic cancer. Overall, we show that PDX are trustworthy pre-clinical models of pancreatic adenocarcinoma including of unresectable tumors. Their multiomics profiling allow the independent analysis of the uncontaminated cancer or stromal compartments and discloses several original therapeutics targets. Citation Format: Remy Nicolle, Yuna Blum, Laetitia Marisa, Celine Loncle, Odile Gayet, Vincent Moutardier, Olivier Turrini, Marc Giovannini, Benjamin Bian, Martin Bigonnet, Marion Rubis, Nabila Elarouci, Lucile Armenoult, Mira Ayadi, Pauline Duconseil, Mohamed Gasmi, Mehdi Ouaissi, Aurélie Maignan, Gwen Lomberk, Jean-Marie Boher, Jacques Ewald, Erwan Bories, Jonathan Garnier, Anthony Goncalves, Flora Poizat, Jean-Luc Raoul, Veronique Secq, Stephane Garcia, Philippe Grandval, Marine Barraud-Blanc, Emmanuelle Norguet, Marine Gilabert, Jean-Robert Delpero, Julie Roques, Ezequiel Calvo, Fabienne Guillaumond, Sophie Vasseur, Raul Urrutia, Aurélien de Reyniès, Nelson Dusetti, Juan Iovanna. Multiomics assessment of the cancer and stromal compartments of patient-derived pancreatic xenografts reveals clinically-relevant subtypes and novel targeted therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 4396. doi:10.1158/1538-7445.AM2017-4396

Muscle-invasive bladder carcinoma (MIBC) constitutes a heterogeneous group of tumors with a poor outcome. Molecular stratification of MIBC may identify clinically relevant tumor subgroups and help to provide effective targeted therapies. From seven series of large-scale transcriptomic data (383 tumors), we identified an MIBC subgroup accounting for 23.5% of MIBC, associated with shorter survival and displaying a basal-like phenotype, as shown by the expression of epithelial basal cell markers. Basal-like tumors presented an activation of the epidermal growth factor receptor (EGFR) pathway linked to frequent EGFR gains and activation of an EGFR autocrine loop. We used a 40-gene expression classifier derived from human tumors to identify human bladder cancer cell lines and a chemically induced mouse model of bladder cancer corresponding to human basal-like bladder cancer. We showed, in both models, that tumor cells were sensitive to anti-EGFR therapy. Our findings provide preclinical proof of concept that anti-EGFR therapy can be used to target a subset of particularly aggressive MIBC tumors expressing basal cell markers and provide diagnostic tools for identifying these tumors.

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.

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.

IntroductionGermline BRCA1 or BRCA2 mutations account for 20-30% of familial clustering of breast cancer. The main indication for BRCA2 screening is currently the family history but the yield of mutations identified in patients selected this way is low.MethodsTo develop more efficient approaches to screening we have compared the gene expression and genomic profiles of BRCA2-mutant breast tumors with those of breast tumors lacking BRCA1 or BRCA2 mutations.ResultsWe identified a group of 66 genes showing differential expression in our training set of 7 BRCA2-mutant tumors and in an independent validation set of 19 BRCA2-mutant tumors. The differentially expressed genes include a prominent cluster of genes from chromosomes 13 and 14 whose expression is reduced. Gene set enrichment analysis confirmed that genes in specific bands on 13q and 14q showed significantly reduced expression, suggesting that the affected bands may be preferentially deleted in BRCA2-mutant tumors. Genomic profiling showed that the BRCA2-mutant tumors indeed harbor deletions on chromosomes 13q and 14q. To exploit this information we have created a simple fluorescence in situ hybridization (FISH) test and shown that it detects tumors with deletions on chromosomes 13q and 14q.ConclusionTogether with previous reports, this establishes that deletions on chromosomes 13q and 14q are a hallmark of BRCA2-mutant tumors. We propose that FISH to detect these deletions would be an efficient and cost-effective first screening step to identify potential BRCA2-mutation carriers among breast cancer patients without a family history of breast cancer.

BACKGROUND: Oligodendroglial tumors are a group of heterogeneous gliomas in terms of clinical, radiological, histological and molecular profiles. Current molecular classification of oligodendroglial tumors identifies 3 groups with distinct clinical outcomes based on two genetic events only: IDH mutation and 1p/19q co-deletion. Integrating data from additional molecular level contributes to refine further this classification and adapt clinical practice accordingly. METHODS: 156 tumors with an oligodendroglial component (Grade II(46), III(100), IV(10)) as well as 22 supportive samples (11 glioblastomas, 2 diffuse astrocytomas, 9 normal brain samples) were profiled transcriptionally (mRNA expression arrays and microRNA sequencing), genomically (SNP arrays) and epigenetically (DNA methylation arrays). Unsupervised consensus classification was performed for each omics separately and by integrating the different omics. RESULTS: A strong correlation was observed between the classification systems obtained from the different omics and 5 subgroups of tumors were robustly identified. The validity of these 5 classes was confirmed on public TCGA data from low grade gliomas (TCGA-LGG). Beyond the 3 well-known molecular classes (1p/19q co-deletion and IDH mutation, IDH mutation only, no IDH mutation and no 1p/19q co-deletion), our multi-omics classification reveals 3 additional subgroups within the group of 1p/19q co-deleted tumors. These 3 subgroups are associated with distinct genomic alterations, distinct expression patterns of cell differentiation markers (from oligodendroglial precursor cells, oligodendrocytes, or neuronal cells), and distinct expression of oncogenic pathways and immune signatures. Follow-up duration of our cohort was not long enough to highlight reliable associations with prognosis but the analysis of TCGA-LGG based on our new 3 subgroups shows a significant association with distinct survival outcomes independently from histologic grade. CONCLUSION: This work represents the first integrative multi-omics analysis of oligodendroglial tumors and enables the refining of their molecular classification. The new classification identifies for the first time distinct molecular subgroups within 1p/19q co-deleted oligodendroglial tumors.

Objectifs Les tumeurs de vessie infiltrant le muscle (TVIM) presentent une grande heterogeneite moleculaire et clinique et, parallelement, les etudes de phase II–III ont rapporte un manque d’efficacite des therapies ciblees. L’objectif de cette etude etait de definir un sous-groupe homogene de tumeurs de vessie au moyen de l’etude du transcriptome et d’identifier dans ce sous-groupe les voies de signalisation pouvant etre ciblees par des therapeutiques. Methodes Les donnees cliniques, histologiques, genomiques et transcriptomiques provenant de 85 TVNIM et de 6 jeux de donnees publiques independants ( n = 298) ont ete utilises comme cohortes de decouverte et de validation respectivement. L’identification des groupes moleculaires a ete realisee par clustering hierarchique consensus. Le groupe moleculaire le plus stable a ete caracterise sur le plan clinique, histopathologique et moleculaire. La sensibilite aux therapies pour ce groupe a ete determinee in vitro par des tests d’inhibition de la proliferation et, in vivo, dans des modeles murins de xenogreffes de lignees cellulaires et dans un modele murin chimio-induit. Resultats Nous avons identifie un sous-groupe (∼ 25 % TVNIM) defini par une signature transcriptomique de 40 genes, caracterise par un pronostic pejoratif, une expression de marqueurs de cellules basales epitheliales, une frequente inflexion malpighienne associee (∼ 50 %), et une activation de la voie EGFR. La signature transcriptomique a permis d’identifier 11 lignees « basal », dont 9 etaient sensibles a l’erlotinib et au cetuximab alors que 1 seule des 11 lignees « non-basal » repondait a ces traitements ciblant EGFR. La sensibilite des cellules tumorales « basal » a l’erlotinib a ete confirmee dans les modeles de xenogreffes chez la souris et dans un modele murin chimio-induit. L’etude en immunohistochimie a montre que le profil « cytokeratines 5/6 diffus et intense/FoxA1 nucleaire nul » presentait une sensibilite de 89 % et une specificite de 95 %. Conclusion Ces resultats demontrent l’existence d’un sous-groupe de type basal parmi les carcinomes urotheliaux de la vessie marque par un pronostic pejoratif. La sensibilite aux traitements anti-EGFR dans les modeles pre-cliniques et les marqueurs mis en evidence pour ce sous-groupe ouvrent des perspectives therapeutiques qui devront etre evaluees dans de futurs essais cliniques.

Introduction Les cancers presentent de nombreuses mutations somatiques, identifiables par le sequencage d’exomes. Certains genes sont egalement inactives par deletion homozygote ou actives par amplification genique dans la tumeur. L’objectif etait d’identifier les genes alteres dans les corticosurrenalomes. Materiel et methodes L’exome de 45 corticosurrenalomes a ete compare a l’ADN non tumoral correspondant. Neuf genes recurrents ont ete sequences sur 77 autres couples tumeurs/leucocytes. Le genome de ces tumeurs a ete egalement analyse par puce SNP. Resultats Les corticosurrenalomes presentent une mediane de 30 mutations somatiques, sauf deux corticosurrenalomes hypermutes (517 et 1364 mutations). Le taux de mutation est correle a la survie a 5 ans (Wilcoxon p = 0,003) et au score de Weiss (ANOVA p = 0,02). Neuf genes sont alteres dans au moins 3/45 corticosurrenalomes passes en exome et en puce SNP : ZNRF43, CTNNB1, TP53, RB1, MEN1, CDKN2A, TERT, DAXX et MED12. Parmi ces genes, ZNRF3, est un nouveau gene suppresseur de tumeurs identifie par cette etude. Il est altere dans 26 des 122 corticosurrenalomes (21 %). ZNRF3 semble moduler la voie Wnt-βcatenine. Dans la meme voie, CTNNB1 est mute dans 20/122 des corticosurrenalomes (16 %). Les alterations de ZNRF3 et CTNNB1 sont mutuellement exclusives. Enfin TP53 est altere dans 20/122 corticosurrenalomes (16 %). Les mutations recurrentes sont retrouvees principalement dans les corticosurrenalomes « agressif » tels que definis par la classification non supervisee du transcriptome. Conclusion Il existe deux types de corticosurrenalomes, l’un de mauvais pronostic avec des mutations specifiques (voie Wnt-βcatenine et voie p53 principalement), l’autre sans mutation recurrente.