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Colorectal cancer (CRC) is highly prevalent in Western society, and increasing evidence indicates strong contributions of environmental factors and the intestinal microbiota to CRC initiation, progression and even metastasis. We have identified a synergistic inflammatory tumor-promoting mechanism through which the resident intestinal microbiota boosts invasive CRC development in an epithelial-to-mesenchymal transition-prone tissue environment. Intestinal epithelial cell (IEC)-specific transgenic expression of the epithelial-to-mesenchymal transition regulator Zeb2 in mice (Zeb2

The term 'immunogenic cell death' (ICD) denotes an immunologically unique type of regulated cell death that enables, rather than suppresses, T cell-driven immune responses that are specific for antigens derived from the dying cells. The ability of ICD to elicit adaptive immunity heavily relies on the immunogenicity of dying cells, implying that such cells must encode and present antigens not covered by central tolerance (antigenicity), and deliver immunostimulatory molecules such as damage-associated molecular patterns and cytokines (adjuvanticity). Moreover, the host immune system must be equipped to detect the antigenicity and adjuvanticity of dying cells. As cancer (but not normal) cells express several antigens not covered by central tolerance, they can be driven into ICD by some therapeutic agents, including (but not limited to) chemotherapeutics of the anthracycline family, oxaliplatin and bortezomib, as well as radiation therapy. In this Trial Watch, we describe current trends in the preclinical and clinical development of ICD-eliciting chemotherapy as partner for immunotherapy, with a focus on trials assessing efficacy in the context of immunomonitoring. ispartof: ONCOIMMUNOLOGY vol:9 issue:1 ispartof: location:United States status: published

High T‐cell infiltration in colorectal cancer (CRC) correlates with a favorable disease outcome and immunotherapy response. This, however, is only observed in a small subset of CRC patients. A better understanding of the factors influencing tumor T‐cell responses in CRC could inspire novel therapeutic approaches to achieve broader immunotherapy responsiveness. Here, we investigated T cell‐suppressive properties of different myeloid cell types in an inducible colon tumor mouse model. The most potent inhibitors of T‐cell activity were tumor‐infiltrating neutrophils. Gene expression analysis and combined in vitro and in vivo tests indicated that T‐cell suppression is mediated by neutrophil‐secreted metalloproteinase activation of latent TGFβ. CRC patient neutrophils similarly suppressed T cells via TGFβ in vitro, and public gene expression datasets suggested that T‐cell activity is lowest in CRCs with combined neutrophil infiltration and TGFβ activation. Thus, the interaction of neutrophils with a TGFβ‐rich tumor microenvironment may represent a conserved immunosuppressive mechanism in CRC., Neutrophil infiltration is a conserved characteristic in human and mouse colon tumors, and is initiated during the formation of early adenomas. Neutrophils contribute to an immune‐suppressive tumor microenvironment through the secretion of MMPs, which activate latent TGFβ stored in the tumor stroma.

Background: The consensus molecular subtypes (CMS) is a transcriptome-based classification of colorectal cancer (CRC) initially described in early-stage cohorts, but the associations of CMS with treatment outcomes in the metastatic setting are yet to be established. This study aimed to evaluate the prognostic impact of CMS classification and its predictive effects for bevacizumab benefit in metastatic CRC by correlative analysis of the AGITG MAX trial. Patients and methods: The MAX trial previously reported improved progression-free survival (PFS) for the addition of bevacizumab (B) to chemotherapy [capecitabine (C)±mitomycin (M)]. Archival primary tumours from 237 patients (50% of trial population) underwent gene expression profiling and classification into CMS groups. CMS groups were correlated to PFS and overall survival (OS). The interaction of CMS with treatment was assessed by proportional hazards model. Results: The distribution of CMS in MAX were CMS1 18%, CMS2 47%, CMS3 12%, CMS4 23%. CMS1 was the predominant subtype in right-sided primary tumours, while CMS2 was the predominant subtype in left-sided. CMS was prognostic of OS (P = 0.008), with CMS2 associated with the best outcome and CMS1 the worst. CMS remained an independent prognostic factor in a multivariate analysis. There was a significant interaction between CMS and treatment (P-interaction = 0.03), for PFS, with hazard ratios (95% CI) for CB+CBM versus C arms in CMS1, 2, 3 and 4: 0.83 (0.43-1.62), 0.50 (0.33-0.76), 0.31 (0.13-0.75) and 1.24 (0.68-2.25), respectively. Conclusions: This exploratory study found that CMS stratified OS outcomes in metastatic CRC regardless of first-line treatment, with prognostic effects of CMS groups distinct from those previously reported in early-stage cohorts. In CMS associations with treatment, CMS2 and possibly CMS3 tumours may preferentially benefit from the addition of bevacizumab to first-line capecitabine-based chemotherapy, compared with other CMS groups. Validation of these findings in additional cohorts is warranted. Clinical trial number: This is a molecular sub-study of MAX clinical trial (NCT00294359). ispartof: Ann Oncol vol:29 issue:11 pages:2240-2246 ispartof: location:England status: published

Immuno-therapeutics aim to activate the body's own immune system against cancer and are one of the most promising cancer treatment strategies, but currently limited by a variable response rate. Biomarkers may help to distinguish those patients most likely to respond to therapy; they may also help guide clinical decision making for combination therapies, dosing schedules, and determining progression versus relapse. However, there is a need to confirm such biomarkers in preferably prospective clinical trials before they can be used in practice. Accordingly, it is essential that clinical trials for immuno-therapeutics incorporate biomarkers. Here, focusing on the specific setting of immune therapies, we discuss both the scientific and logistical hurdles to identifying potential biomarkers and testing them in clinical trials.

Mutations in KRAS and/or BRAF that activate the ERK kinase are frequently found in colorectal cancer (CRC) and drive resistance to targeted therapies. Therefore, the identification of therapeutic targets that affect multiple signaling pathways simultaneously is crucial for improving the treatment of patients with KRAS or BRAF mutations. The proprotein convertase furin activates several oncogenic protein precursors involved in the ERK-MAPK pathway by endoproteolytic cleavage. Here we show that genetic inactivation of furin suppresses tumorigenic growth, proliferation, and migration in KRAS or BRAF mutant CRC cell lines but not in wild-type KRAS and BRAF cells. In a mouse xenograft model, these KRAS or BRAF mutant cells lacking furin displayed reduced growth and angiogenesis, and increased apoptosis. Mechanistically, furin inactivation prevents the processing of various protein pecursors including proIGF1R, proIR, proc-MET, proTGF-β1 and NOTCH1 leading to potent and durable ERK-MAPK pathway suppression in KRAS or BRAF mutant cells. Furthermore, we identified genes involved in activating the ERK-MAPK pathway, such as PTGS2, which are downregulated in the KRAS or BRAF mutant cells after furin inactivation but upregulated in wild-type KRAS and BRAF cells. Analysis of human colorectal tumor samples reveals a positive correlation between enhanced furin expression and KRAS or BRAF expression. These results indicate that furin plays an important role in KRAS or BRAF-associated ERK-MAPK pathway activation and tumorigenesis, providing a potential target for personalized treatment. ispartof: ONCOGENE vol:39 issue:17 pages:3571-3587 ispartof: location:England status: published

BackgroundBRAF mutation occurs in 8-15% of colon cancers (CC), and is associated with poor prognosis in metastatic disease. Compared to wild-type BRAF (BRAFWT) disease, stage II/III CC patients with BRAF mutant (BRAFMT) tumors have shorter overall survival after relapse; however, time-to-relapse is not significantly different. The aim of this investigation was to identify, and validate, novel predictors of relapse of stage II/III BRAFMT CC.Patients and methodsWe used gene expression data from a cohort of 460 patients (GSE39582) to perform a supervised classification analysis based on risk-of-relapse within BRAFMT stage II/III CC, to identify transcriptomic biomarkers associated with prognosis within this genotype. These findings were validated using immunohistochemistry in an independent population-based cohort of Stage II/III CC (n=691), applying Cox proportional hazards analysis to determine associations with survival.ResultsHigh gene expression levels of Bcl-xL, a key regulator of apoptosis, were associated with increased risk of relapse, specifically in BRAFMT tumors (HR=8.3, 95% CI 1.7-41.7), but not KRASMT/BRAFWT or KRASWT/BRAFWT tumors. High Bcl-xL protein expression in BRAFMT, untreated, stage II/III CC was confirmed to be associated with an increased risk of death in an independent cohort (HR=12.13, 95% CI 2.49-59.13). Additionally, BRAFMT tumors with high levels of Bcl-xL protein expression appeared to benefit from adjuvant chemotherapy (P for interaction =0.006), indicating the potential predictive value of Bcl-xL expression in this setting.ConclusionsThese findings provide evidence that Bcl-xL gene and/or protein expression identifies a poor prognostic subgroup of BRAFMT stage II/III CC patients, who may benefit from adjuvant chemotherapy.Key MessageUsing a combination of computational biology discovery and immunohistochemistry validation in independent patient cohorts, we show that high expression of the apoptosis regulator Bcl-xL is associated with disease relapse specifically within BRAF mutant stage II/III colon cancer.This data could enable tailored disease management to reduce relapse rates in the most aggressive subtype.

Metastatic colorectal carcinoma (mCRC) is a heterogeneous disease with differing outcomes and clinical responses and poor prognosis. CRCs can be characterised by their primary tumour location within the colon. The left-sided colon, derived from the hindgut, includes the distal third of the transverse colon, splenic flexure, descending colon, sigmoid colon and rectum. The right-sided colon, derived from the midgut, includes the proximal two-thirds of the transverse colon, ascending colon and caecum. Sometimes, the rectum is described separately, despite originating from the hindgut, and in many clinical series, the left-sided colon includes only tumours within and distal to the splenic flexure. Differences in the microbiome, clinical characteristics and chromosomal and molecular characteristics have been reported between the right and left side of the colon, regardless of how this is defined. There is now strong evidence from clinical studies in patients with mCRC for the prognostic effect of primary tumour location. The impact of primary colonic tumour location on response to treatment is now under investigation in a large number of clinical studies in patients with mCRC. In this review, we summarise the microbiome, clinical, chromosomal and molecular differences associated with the primary location of CRC. We present an overview of the proven prognostic impact of primary tumour location for patients with mCRC and discuss emerging data for the predictive impact of primary tumour location on clinical outcome.

Critical driver genomic events in colorectal cancer have been shown to affect the response to targeted agents that were initially developed under the 'one gene, one drug' paradigm of precision medicine. Our current knowledge of the complexity of the cancer genome, clonal evolution patterns under treatment pressure and pharmacodynamic effects of target inhibition support the transition from a one gene, one drug approach to a 'multi-gene, multi-drug' model when making therapeutic decisions. Better characterization of the transcriptomic subtypes of colorectal cancer, encompassing tumour, stromal and immune components, has revealed convergent pathway dependencies that mandate a 'multi-molecular' perspective for the development of therapies to treat this disease.

Immunotherapy for metastatic colorectal cancer is effective only for mismatch repair-deficient tumors with high microsatellite instability that demonstrate immune infiltration, suggesting that tumor cells can determine their immune microenvironment. To understand this cross-talk, we analyzed the transcriptome of 91,103 unsorted single cells from 23 Korean and 6 Belgian patients. Cancer cells displayed transcriptional features reminiscent of normal differentiation programs, and genetic alterations that apparently fostered immunosuppressive microenvironments directed by regulatory T cells, myofibroblasts and myeloid cells. Intercellular network reconstruction supported the association between cancer cell signatures and specific stromal or immune cell populations. Our collective view of the cellular landscape and intercellular interactions in colorectal cancer provide mechanistic information for the design of efficient immuno-oncology treatment strategies.

PURPOSE To determine the predictive and prognostic value of the consensus molecular subtypes (CMSs) of colorectal cancer (CRC) that represent a merging of gene expression–based features largely in primary tumors from six independent classification systems and provide a framework for capturing the intrinsic heterogeneity of CRC in patients enrolled in CALGB/SWOG 80405. PATIENTS AND METHODS CALGB/SWOG 80405 is a phase III trial that compared the addition of bevacizumab or cetuximab to infusional fluorouracil, leucovorin, and oxaliplatin or fluorouracil, leucovorin, and irinotecan as first-line treatment of advanced CRC. We characterized the CMS classification using a novel NanoString gene expression panel on primary CRCs from 581 patients enrolled in this study to assess the prognostic and predictive value of CMSs in these patients. RESULTS The CMSs are highly prognostic for overall survival (OS; P < .001) and progression-free survival (PFS; P < .001). Furthermore, CMSs were predictive for both OS ( P for interaction < .001) and PFS ( P for interaction = .0032). In the CMS1 cohort, patients treated with bevacizumab had a significantly longer OS than those treated with cetuximab ( P < .001). In the CMS2 cohort, patients treated with cetuximab had a significantly longer OS than patients treated with bevacizumab ( P = .0046). CONCLUSION These findings highlight the possible clinical utility of CMSs and suggests that refinement of the CMS classification may provide a path toward identifying patients with metastatic CRC who are most likely to benefit from specific targeted therapy as part of the initial treatment.

Purpose:The cytokine IL22 promotes tumor progression in murine models of colorectal cancer. However, the clinical significance of IL22 in human colorectal cancer remains unclear. We sought to determine whether the IL22 pathway is associated with prognosis in human colorectal cancer, and to identify mechanisms by which IL22 can influence disease progression.Experimental Design:Transcriptomic data from stage II/III colon cancers in independent discovery (GSE39582 population-based cohort, N = 566) and verification (PETACC3 clinical trial, N = 752) datasets were used to investigate the association between IL22 receptor expression (encoded by the genes IL22RA1 and IL10RB), tumor mutation status, and clinical outcome using Cox proportional hazard models. Functional interactions between IL22 and mutant KRAS were elucidated using human colorectal cancer cell lines and primary tumor organoids.Results:Transcriptomic analysis revealed a poor-prognosis subset of tumors characterized by high expression of IL22RA1, the alpha subunit of the heterodimeric IL22 receptor, and KRAS mutation [relapse-free survival (RFS): HR = 2.93, P = 0.0006; overall survival (OS): HR = 2.45, P = 0.0023]. KRAS mutations showed a similar interaction with IL10RB and conferred the worst prognosis in tumors with high expression of both IL22RA1 and IL10RB (RFS: HR = 3.81, P = 0.0036; OS: HR = 3.90, P = 0.0050). Analysis of human colorectal cancer cell lines and primary tumor organoids, including an isogenic cell line pair that differed only in KRAS mutation status, showed that IL22 and mutant KRAS cooperatively enhance cancer cell proliferation, in part through augmentation of the Myc pathway.Conclusions:Interactions between KRAS and IL22 signaling may underlie a previously unrecognized subset of clinically aggressive colorectal cancer that could benefit from therapeutic modulation of the IL22 pathway.

TPS157 Background: Patritumab deruxtecan (HER3-DXd; U3-1402) is a novel, investigational antibody drug conjugate comprising an anti-HER3 monoclonal antibody, a tetrapeptide-based linker, and a topoisomerase I inhibitor payload. Ongoing clinical trials of HER3-DXd in pts with metastatic breast cancer or non-small cell lung cancer have shown promising clinical activity and acceptable safety. HER3 (human epidermal growth receptor 3), a member of the tyrosine kinase receptor family, is overexpressed in most CRC tumors and associated with an adverse prognosis. Significant tumor regression with HER3-DXd has been observed in CRC murine xenograft models, regardless of KRAS mutation status. Here we introduce the design of a phase 2 study (U31402-A-U202) that is evaluating HER3-DXd in previously treated pts with advanced/metastatic CRC. Methods: U31402-A-U202 (NCT04479436) is an open-label, multicenter phase 2 study that will enroll 80 pts in the USA, Europe and Asia. Pts are enrolled who are aged ≥ 18 years with advanced/metastatic colorectal adenocarcinoma that is resistant/refractory/intolerant to ≥ 2 prior lines of therapy including a fluoropyrimidine, irinotecan, a platinum agent, an anti-EGFR agent (if clinically indicated), an anti-VEGF agent (unless contraindicated [CI]), and an immune checkpoint inhibitor (unless CI) for microsatellite instability-high CRC. Pts with current/previous interstitial lung disease or clinically severe pulmonary compromise are excluded. Archival tumor biopsy and pre-treatment tumor biopsy are collected from all pts at screening, with HER3 protein expression measured by immunohistochemistry (IHC). In part 1, results of the HER3 IHC assay from the pre-treatment tumor biopsy are used to assign pts into 1 of 2 cohorts (C). C1: HER3 high (IHC 3+, 2+), n = 24; C2: HER3 low/negative (IHC 1+, 0), n = 12. Pts receive 5.6 mg/kg HER3-DXd IV every 3 weeks. An interim futility analysis will be conducted separately for C1 and C2 and will determine enrollment in part 2, with 2 potential scenarios: enrollment continues irrespective of HER3 IHC status, or enrollment continues in HER3 high pts only. The primary objective is the evaluation of the antitumor activity of HER3-DXd as measured by objective response rate (ORR) (assessed by BICR according to RECIST v1.1). ORR will be summarized with the 2-sided 95% confidence interval. Secondary objectives include the evaluation of efficacy as measured by ORR (assessed by investigator according to RECIST v1.1), duration of response, time to tumor response, disease control rate, progression-free survival (assessed by investigator and BICR according to RECIST v1.1), overall survival, safety and tolerability, HER3 protein expression in tumor tissue and relationship with efficacy, and pharmacokinetic properties. Clinical trial information: NCT04479436.

The ZIC2 transcription factor is one of the genes most commonly mutated in Holoprosencephaly (HPE) probands. Studies in cultured cell lines and mice have shown a loss of ZIC2 function is the pathogenic mechanism but the molecular details of this ZIC2 requirement remain elusive. HPE arises when signals that direct morphological and fate changes in the developing brain and facial primordia are not sent or received. One critical signal is sent from the prechordal plate (PrCP) which develops beneath the ventral forebrain. An intact NODAL signal transduction pathway and functional ZIC2 are both required for PrCP establishment. We now show that ZIC2 acts downstream of the NODAL signal during PrCP development. ZIC2 physically interacts with SMAD2 and SMAD3, the receptor activated proteins that control transcription in a NODAL dependent manner. Together SMAD3 and ZIC2 regulate FOXA2 transcription in cultured cells and Zic2 also controls the foxA2 expression during Xenopus development. Variant forms of the ZIC2 protein, associated with HPE in man or mouse, are deficient in their ability to influence SMAD-dependent transcription. These findings reveal a new mechanism of NODAL signal transduction in the mammalian node and provide the first molecular explanation of how ZIC2 loss-of-function precipitates HPE.

BACKGROUND: Precision cancer medicine depends on defining distinct tumour subgroups using biomarkers that may occur at very modest frequencies. One such subgroup comprises patients with exceptionally mutated (ultramutated) cancers caused by mutations that impair DNA polymerase epsilon (POLE) proofreading.METHODS: We examined the association of POLE proofreading domain mutation with clinicopathological variables and immune response in colorectal cancers from clinical trials (VICTOR, QUASAR2, and PETACC-3) and colorectal cancer cohorts (Leiden University Medical Centre 1 and 2, Oslo 1 and 2, Bern, AMC-AJCC-II, and Epicolon-1). We subsequently investigated its association with prognosis in stage II/III colorectal cancer by Cox regression of pooled individual patient data from more than 4500 cases from these studies.FINDINGS: Pathogenic somatic POLE mutations were detected in 66 (1·0%) of 6517 colorectal cancers, and were mutually exclusive with mismatch repair deficiency (MMR-D) in the 6277 cases for whom both markers were determined (none of 66 vs 833 [13·4%] of 6211; pINTERPRETATION: POLE proofreading domain mutations identify a subset of immunogenic colorectal cancers with excellent prognosis. This association underscores the importance of rare biomarkers in precision cancer medicine, but also raises important questions about how to identify and implement them in practice.FUNDING: Cancer Research UK, Academy of Medical Sciences, Health Foundation, EU, ERC, NIHR, Wellcome Trust, Dutch Cancer Society, Dutch Digestive Foundation.

No abstract available

TPS266 Background: Patients (pts) with MSI-H/dMMR mCRC treated with CT have poorer outcomes than pts with microsatellite stable/MMR proficient mCRC. NIVO (anti–programmed death [PD]-1) and IPI (anti–cytotoxic T lymphocyte antigen-4 [CTLA-4]) are immune checkpoint inhibitors that act synergistically and promote antitumor immune response by complementary mechanisms. NIVO±IPI received accelerated US FDA approval for MSI-H/dMMR mCRC that progressed after fluoropyrimidine, oxaliplatin, and irinotecan treatment based on the phase 2, non-randomized, multicohort CheckMate 142 study. Indirect comparisons suggest that NIVO (3 mg/kg) + low-dose IPI (1 mg/kg) provides improved clinical benefit vs NIVO (investigator-assessed [INV] objective response rate [ORR] 55% vs 31%; 12-month [mo] INV progression-free survival [PFS] rate 71% vs 50%; 12-mo overall survival [OS] rate 85% vs 73%) with a favorable benefit-risk profile for previously treated MSI-H/dMMR mCRC (Overman et al. JCO 2018). NIVO+low-dose IPI also demonstrated robust and durable clinical benefit in first-line MSI-H/dMMR mCRC (INV ORR 64%; 12-mo INV PFS rate 77%; 12-mo OS rate 84%; Lenz et al. ASCO 2019, #3521). To date, no prospective phase 3 studies have reported results for anti–PD-1, anti–PD-1 + anti–CTLA-4, or CT in MSI-H/dMMR mCRC; these treatments will be evaluated in the international, multicenter, open-label, randomized, phase 3 CheckMate 8HW (NCT04008030) study. Methods: Approximately 494 pts aged ≥18 years with histologically confirmed recurrent or mCRC, irrespective of prior treatment with CT and/or targeted agents, not amenable to surgery, and with known tumor MSI-H or dMMR status, and Eastern Cooperative Oncology Group performance status ≤1 will be randomized to receive NIVO, NIVO+IPI, or investigator’s choice CT (pts in the CT arm can receive NIVO+IPI upon progression). The primary endpoint is PFS, assessed by blinded independent central review (BICR). Secondary endpoints include PFS by INV, ORR and disease control rate by BICR and INV, OS, time to and duration of response. Exploratory endpoints include safety. Clinical trial information: NCT04008030.

247 Background: This analysis was undertaken to forecast survival and enhance treatment decisions for patients (pts) with colorectal cancer (CRC) with liver metastases sensitive to folinic acid, fluorouracil and irinotecan (FOLFIRI) alone [F] or in combination with cetuximab [FC] using simple quantitative radiomic changes between CT scans at baseline and 8 weeks. Methods: We retrospectively analyzed 667 pts with KRAS-unselected metastatic CRC in NCT00154102 treated with F and FC. CT quality was classified as high (HQ) or standard (SQ), and four data sets were created and named by treatment quality. Pts were randomly assigned 1:2 to training or validation sets: FCHQ, 38/78 pts; FCSQ, 62/124 pts; FHQ, 51/78 pts; FSQ, 78/158 pts. A machine-learning signature was trained using data set FCHQ to classify pts as treatment-sensitive or treatment-insensitive using just 4 of 3,499 potential radiomic imaging features. Performance was calibrated/validated using ROC curves. Hazard ratios (HRs) and Cox regression models were used to evaluate association with overall survival (OS). Results: The signature used decrease in tumor heterogeneity plus boundary infiltration to successfully predict sensitivity to FC (FCHQ: AUC, 0.80; FCSQ: AUC, 0.72) but failed with non-cetuximab regimens (FHQ: AUC, 0.59; FSQ: AUC, 0.55). The radiomic signature outperformed existing biomarkers ( KRAS mutational status and tumor shrinkage by RECIST 1.1) for sensitivity to cetuximab-based therapy and was strongly associated with OS in the cetuximab-containing sets FCHQ (HR, 44.3; p = 0.0001) and FCSQ (HR, 6.5; p = 0.005). Conclusions: This signature, derived from simple radiomic analysis of tumor imaging phenotype using only standard-of-care CT scans, appeared to be treatment-specific and was superior to all tested prognostic biomarkers. The signature provided early prediction of sensitivity and survival and could be used to guide treatment continuation decisions.

SPECTA is the translational research platform from the European Organisation for Research and Treatment of Cancer (EORTC), which facilitates pan-European research projects by providing a comprehensive infrastructure: a single protocol and Patient Informed Consent to enrol patients with cancer, a centralised database for clinical data collection (including long-term follow-up and quality of life), a centralised biobank and quality control sample workflow, expert molecular laboratories dedicated to the needs of the translational research projects. So far, 11 countries with 36 sites are open for recruitment with 43 authorized investigators. Two SPECTA projects focus on rare populations. The first, AYA (Adolescent and Young Adults) enrols patients aged between 12 and 29 years old, diagnosed with high grade glioma or sarcoma. AYA is a pilot study with a strong collaboration, between DKFZ and EORTC, aiming at diagnosis confirmation (central pathology review by pathologist experts and methylation diagnosis), and extensive molecular analysis (WES, RNAseq and methylation array). The aim is not only to have a direct impact on patients through the clinical advice provided to the treating physician by the molecular tumor board, but also to build knowledge for future clinical trials in this population with unmet needs. The second, Arcagen, is a collaborative project with the EUropean network for RAre CANcer (EURACAN), the European network for rare cancer. This project, with the support of Roche, aims at building a clinically annotated genomic database (NGS panels for FMI) of 1,000 rare cancer patients from the 10 EURACAN domains. So far, 81 patients have been recruited: sarcoma (n=43), thymic malignancies (n=16), germ cell tumor (n=10), and rare head and neck tumor (n=15). Druggable alterations were found in about 15% of patients. Molecular reports will be sent to local clinicians, the study results will be used for designing for the next generation of clinical trials in adult rare cancers. The last project currently enrolling in SPECTA is IMMUcan, an Innovative Medicine Initiative project. IMMUcan will generate broad molecular (WES and RNAseq) and cellular profiling data (multiplex immunofluorescence and imaging mass cytometry) of tumor and its microenvironment. Integration of this information with clinical data, will promote understanding on how the immune system and tumors interact, and the impact of current therapeutic interventions. For this purpose, we will enrol 3,000 patients with NSCLC, HNSCC, breast, colorectal and renal cell cancers. For all projects, we faced recurrent issues regarding tumor and peripheral sample quality. We overcomed those issues by performing optimization studies for pan European collection of biological material (such as PBMCs, ctDNA, vesicles or FFPE slides stability for imaging). SPECTA is an academic solution for next level precision medicine, with all the clinical, operational and scientific challenges that it implies. Citation Format: Marie Vinches, Teresa de Rojas, Aleksandra Stevovic, Martin Mccabe, Jean Yves Blay, Vassilis Golfinopoulos, Sabine Tejpar, Marie Morfouace. SPECTA: The EORTC translational research platform for Europe [abstract]. In: Proceedings of the AACR-NCI-EORTC International Conference on Molecular Targets and Cancer Therapeutics; 2019 Oct 26-30; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2019;18(12 Suppl):Abstract nr A075. doi:10.1158/1535-7163.TARG-19-A075

BACKGROUND:Colorectal cancer is an epigenetically heterogeneous disease, however the extent and spectrum of the CpG Island Methylator Phenotype (CIMP) is not clear.RESULTSAn unselected cohort of 216 colorectal cancers clustered into five clinically and molecularly distinct subgroups using Illumina 450K DNA methylation arrays. CIMP-High cancers were most frequent in the proximal colons of female patients. These dichotomised into CIMP-Hl and CIMP-H2 based on methylation profile which was supported by over representation of BRAF (74%, PKRAS (55%, P78). We identified oncogenes susceptible to gene body methylation and Wnt pathway antagonists resistant to gene body methylation. CIMP cluster specific mutations were observed for genes involved in chromatin remodelling, such as in the SWI/SNF and NuRD complexes, suggesting synthetic lethality.CONCLUSIONThere are five clinically and molecularly distinct subgroups of colorectal cancer based on genome wide epigenetic profiling. These analyses highlighted an unidentified role for gene body methylation in progression of serrated neoplasia. Subgroup-specific mutation of distinct epigenetic regulator genes revealed potentially druggable vulnerabilities for these cancers, which may provide novel precision medicine approaches.

In the last decade, the amount of investigations on the involvement of ZIC genes in the cancer field have exponentially expanded. In most cancer types, promoter methylation leads to silenced ZIC family members, but specific subsets of patients clearly show increased expression of one or head-to-head located ZIC genes in the respective tumor tissue. It is unclear at this stage how these transcription factors contribute to tumorigenesis, but the potential implications in pathways that are most frequently mutated in cancer such as the canonical Wnt, TGF-beta, and STAT-3 pathway are evident. By exploring well-established developmental models, researchers were able to position ZIC genes not only as classical transcription factors but also as cofactors of chromatin remodeling complexes that are crucial for maintenance of the cell but also during differentiation and maturation of ZIC-expressing tissues in vivo. The translation of this obtained evidence to the cancer field will be challenging but will indisputably lead to a better understanding how the factors can contribute to the tumor development in the given subsets of patients.

In the last decade, the amount of investigations on the involvement of ZIC genes in the cancer field have exponentially expanded. In most cancer types, promoter methylation leads to silenced ZIC family members, but specific subsets of patients clearly show increased expression of one or head-to-head located ZIC genes in the respective tumor tissue. It is unclear at this stage how these transcription factors contribute to tumorigenesis, but the potential implications in pathways that are most frequently mutated in cancer such as the canonical Wnt, TGF-beta, and STAT-3 pathway are evident. By exploring well-established developmental models, researchers were able to position ZIC genes not only as classical transcription factors but also as cofactors of chromatin remodeling complexes that are crucial for maintenance of the cell but also during differentiation and maturation of ZIC-expressing tissues in vivo. The translation of this obtained evidence to the cancer field will be challenging but will indisputably lead to a better understanding how the factors can contribute to the tumor development in the given subsets of patients.

Objectif La FAPA (association belge pour la polypose adenomateuse familiale) a ete creee en 1993 dans le but d’enregistrer les patients atteints de polypose adenomateuse familiale (FAP) Methode Les donnees de tous les patients inclus de maniere prospective dans le registre belge FAPA entre 1993 et 2018 ont ete analysees. Resultats Il y avait 442 patients de 199 familles avec un âge median de 47 (2–88) et un âge median au diagnostic de 23,5 (1–69) au moment du diagnostic. Un nombre median de 1 (1–7) tumeurs desmoides, principalement intra-abdominales, etaient presentes chez 78 patients (18 %). Un cancer du tractus gastro-intestinal superieur a ete diagnostique a l’âge median de 57 (22 a 83) ans chez 36 (8,1 %) des patients. Un cancer colorectal a ete diagnostique chez 100 patients (22,6 %) a un âge median de 43,5 ans (15 a 72 ans) et etait reparti entre 62/159 (39 %) probands versus 38/283 (13 %) patients depistes (p Conclusion Depuis la creation du registre belge de la polypose, l’enregistrement centralise avec identification et examen prophylactique des apparentes a risque a permis une amelioration substantielle du pronostic.

ObjectiveSerrated colorectal cancer (CRC) accounts for approximately 25% of cases and includes tumours that are among the most treatment resistant and with worst outcomes. This CRC subtype is associated with activating mutations in the mitogen-activated kinase pathway gene, BRAF, and epigenetic modifications termed the CpG Island Methylator Phenotype, leading to epigenetic silencing of key tumour suppressor genes. It is still not clear which (epi-)genetic changes are most important in neoplastic progression and we begin to address this knowledge gap herein.DesignWe use organoid culture combined with CRISPR/Cas9 genome engineering to sequentially introduce genetic alterations associated with serrated CRC and which regulate the stem cell niche, senescence and DNA mismatch repair.ResultsTargeted biallelic gene alterations were verified by DNA sequencing. Organoid growth in the absence of niche factors was assessed, as well as analysis of downstream molecular pathway activity. Orthotopic engraftment of complex organoid lines, but not BrafV600E alone, quickly generated adenocarcinoma in vivo with serrated features consistent with human disease. Loss of the essential DNA mismatch repair enzyme, Mlh1, led to microsatellite instability. Sphingolipid metabolism genes are differentially regulated in both our mouse models of serrated CRC and human CRC, with key members of this pathway having prognostic significance in the human setting.ConclusionWe generate rapid, complex models of serrated CRC to determine the contribution of specific genetic alterations to carcinogenesis. Analysis of our models alongside patient data has led to the identification of a potential susceptibility for this tumour type.

An international panel of multidisciplinary experts convened to develop recommendations for managing patients with colorectal cancer (CRC) and synchronous liver metastases (CRCLM). A modified Delphi method was used. CRCLM is defined as liver metastases detected at or before diagnosis of the primary CRC. Early and late metachronous metastases are defined as those detected ⩽12months and >12months after surgery, respectively. To provide information on potential curability, use of high-quality contrast-enhanced computed tomography (CT) before chemotherapy is recommended. Magnetic resonance imaging is increasingly being used preoperatively to aid detection of subcentimetric metastases, and alongside CT in difficult situations. To evaluate operability, radiology should provide information on: nodule size and number, segmental localization and relationship with major vessels, response after neoadjuvant chemotherapy, non-tumoral liver condition and anticipated remnant liver volume. Pathological evaluation should assess response to preoperative chemotherapy for both the primary tumour and metastases, and provide information on the tumour, margin size and micrometastases. Although the treatment strategy depends on the clinical scenario, the consensus was for chemotherapy before surgery in most cases. When the primary CRC is asymptomatic, liver surgery may be performed first (reverse approach). When CRCLM are unresectable, the goal of preoperative chemotherapy is to downsize tumours to allow resection. Hepatic resection should not be denied to patients with stable disease after optimal chemotherapy, provided an adequate liver remnant with inflow and outflow preservation remains. All patients with synchronous CRCLM should be evaluated by a hepatobiliary multidisciplinary team. publisher: Elsevier articletitle: Managing synchronous liver metastases from colorectal cancer: A multidisciplinary international consensus journaltitle: Cancer Treatment Reviews articlelink: http://dx.doi.org/10.1016/j.ctrv.2015.06.006 content_type: article copyright: Copyright © 2015 The Authors. Published by Elsevier Ltd. ispartof: Cancer Treatment Reviews vol:41 issue:9 pages:729-41 ispartof: location:Netherlands status: published

Background: An everyday clinical practice dilemma in the 20–30% of metastatic colorectal cancer (CRC) patients that have not been operated on their primary tumour, is, under which specific histopathology and molecular circumstances, an endoscopic biopsy could be considered adequate to provide a representative RAS/BRAF molecular status to guide treatment. Methods: A consecutive series of 193 paired biopsy and primary CRC tumour samples between August 2008 and 2010 available in the Department of Pathology archives, University Hospitals, KU Leuven were retrieved. For a pair to be included, in the endoscopic biopsy, 20% of invasive adenocarcinoma cells should be present and enough slides to yield an extracted DNA concentration of ⩾5 ng μl−1, and no

Background & AimsCategorization of colon cancers into distinct subtypes using a combination of pathway-based biomarkers could provide insight into stage-independent variability in outcomes.MethodsWe used a polymerase chain reaction–based assay to detect mutations in BRAF (V600E) and in KRAS in 2720 stage III cancer samples, collected prospectively from patients participating in an adjuvant chemotherapy trial (NCCTG N0147). Tumors deficient or proficient in DNA mismatch repair (MMR) were identified based on detection of MLH1, MSH2, and MSH6 proteins and methylation of the MLH1 promoter. Findings were validated using tumor samples from a separate set of patients with stage III cancer (n = 783). Association with 5-year disease-free survival was evaluated using Cox proportional hazards models.ResultsTumors were categorized into 5 subtypes based on MMR status and detection of BRAF or KRAS mutations which were mutually exclusive. Three subtypes were MMR proficient: those with mutations in BRAF (6.9% of samples), mutations in KRAS (35%), or tumors lacking either BRAF or KRAS mutations (49%). Two subtypes were MMR deficient: the sporadic type (6.8%) with BRAF mutation and/or or hypermethylation of MLH1 and the familial type (2.6%), which lacked BRAFV600E or hypermethylation of MLH1. A higher percentage of MMR-proficient tumors with BRAFV600E were proximal (76%), high-grade (44%), N2 stage (59%), and detected in women (59%), compared with MMR-proficient tumors without BRAFV600E or KRAS mutations (33%, 19%, 41%, and 42%, respectively; all P < .0001). A significantly lower proportion of patients with MMR-proficient tumors with mutant BRAF (hazard ratio = 1.43; 95% confidence interval: 1.11–1.85; Padjusted = .0065) or mutant KRAS (hazard ratio = 1.48; 95% confidence interval: 1.27–1.74; Padjusted < .0001) survived disease-free for 5 years compared with patients whose MMR-proficient tumors lacked mutations in either gene. Disease-free survival rates of patients with MMR-deficient sporadic or familial subtypes was similar to those of patients with MMR-proficient tumors without BRAF or KRAS mutations. The observed differences in survival rates of patients with different tumor subtypes were validated in an independent cohort.ConclusionsWe identified subtypes of stage III colon cancer, based on detection of mutations in BRAF (V600E) or KRAS, and MMR status that show differences in clinical and pathologic features and disease-free survival. Patients with MMR-proficient tumors and BRAF or KRAS mutations had statistically shorter survival times than patients whose tumors lacked these mutations. The tumor subtype found in nearly half of the study cohort (MMR-proficient without BRAFV600E or KRAS mutations) had similar outcomes to those of patients with MMR-deficient cancers.

ABSTRACT The VEGF- (bevacizumab) and EGFR- (cetuximab and panitumumab) targeting monoclonal antibodies have become integral components of the first-line treatment strategies for patients with metastatic colorectal cancer (mCRC). Increasingly combination chemotherapy, with or without a targeted agent, is being used to facilitate curative liver resection and improve survival rates in patients with initially unresectable but potentially resectable mCRC. Currently, the only selective marker for the treatment of patients with mCRC is tumor RAS mutational status. BRAF status is a strong prognostic indicator. Medical and clinical oncologists from Central Asia, Russia, the Middle East, Africa and Turkey reviewed data for the use of targeted agents in the treatment of patients with mCRC and have formed recommendations for the biological of choice first-line for patients with mCRC.

BACKGROUND: Although colon cancer (CC) with microsatellite instability (MSI) has a more favorable prognosis than microsatellite stable (MSS) CC, the impact varies according to clinicopathological parameters. We studied how MSI status affects prognosis in a trial-based cohort of stage II and III CC patients treated with 5-fluorouracil (5-FU)/leucovorin or FOLFIRI. MATERIALS AND METHODS: Tissue specimens of 1254 patients were tested for 10 different loci and were classified as MSI-high (MSI-H) when three or more loci were unstable and MSS otherwise. Study end points were overall survival (OS) and relapse-free survival (RFS). RESULTS: In stage II, RFS and OS were better for patients with MSI-H than with MSS CC [hazard ratio (HR) 0.26, 95% CI 0.10-0.65, P = 0.004 and 0.16, 95% CI 0.04-0.64, P = 0.01). In stage III, RFS was slightly better for patients with MSI-H CC (HR 0.67, 95% CI 0.46-0.99, P = 0.04), but the difference was not statistically significant for OS (HR 0.70, 95% CI 0.44-1.09, P = 0.11). Outcomes for patients with MSI-H CC were not different between the two treatment arms. RFS was better for patients with MSI-H than with MSS CC in the right and left colon, whereas for OS this was significant only in the right colon. For patients with KRAS- and BRAF-mutated CC, but not for double wild-type patients, RFS and OS were significantly better when the tumors were also MSI-H. An interaction test was statistically significant for KRAS and MSI status (P = 0.005), but not for BRAF status (P = 0.14). CONCLUSIONS: Our results confirm that for patients with stage II CC but less so for those with stage III MSI-H is strongly prognostic for RFS and OS. In the presence of 5-FU treatment, stage II patients with MSI-H tumors maintain their survival advantage in comparison with MSS patients and adding irinotecan has no added benefit. CLINICALTRIALSGOV IDENTIFIER: NCT00026273.

Altres ajuts: This work was partially supported by grant UM1 CA167551 from the National Cancer Institute (NCI), National Institutes of Health (NIH), and through cooperative agreements with members of the Colon Cancer Family Registry (CCFR) and Principal Investigators. Centers contributing to this analysis include the Seattle Colorectal Cancer Family Registry (U01/U24CA074794), Australasian Colorectal Cancer Family Registry (U01 CA074778 and U01/U24 CA097735), Mayo Clinic Cooperative Family Registry for Colon Cancer Studies (U01/U24 CA074800), and Ontario Familial Colorectal Cancer Registry (U01/U24 CA074783). This work was also supported by NCI/NIH grant K07CA172298 and K05CA152715 (to AIP). The content of this article does not necessarily reflect the views or policies of the NIH or any of the collaborating centers in the CCFR, nor does mention of trade names, commercial products, or organizations imply endorsement by the US Government. This study was partly supported by the "Norwegian Cancer Society" and the "Research Council of Norway" (no grants apply). TNM staging alone does not accurately predict outcome in colon cancer (CC) patients who may be eligible for adjuvant chemotherapy. It is unknown to what extent the molecular markers microsatellite instability (MSI) and mutations in BRAF or KRAS improve prognostic estimation in multivariable models that include detailed clinicopathological annotation. After imputation of missing at random data, a subset of patients accrued in phase 3 trials with adjuvant chemotherapy (n = 3016)-N0147 (NCT00079274) and PETACC3 (NCT00026273)-was aggregated to construct multivariable Cox models for 5-year overall survival that were subsequently validated internally in the remaining clinical trial samples (n = 1499), and also externally in different population cohorts of chemotherapy-treated (n = 949) or -untreated (n = 1080) CC patients, and an additional series without treatment annotation (n = 782). TNM staging, MSI and BRAF V600E mutation status remained independent prognostic factors in multivariable models across clinical trials cohorts and observational studies. Concordance indices increased from 0.61-0.68 in the TNM alone model to 0.63-0.71 in models with added molecular markers, 0.65-0.73 with clinicopathological features and 0.66-0.74 with all covariates. In validation cohorts with complete annotation, the integrated time-dependent AUC rose from 0.64 for the TNM alone model to 0.67 for models that included clinicopathological features, with or without molecular markers. In patient cohorts that received adjuvant chemotherapy, the relative proportion of variance explained (R 2) by TNM, clinicopathological features and molecular markers was on an average 65%, 25% and 10%, respectively. Incorporation of MSI, BRAF V600E and KRAS mutation status to overall survival models with TNM staging improves the ability to precisely prognosticate in stage II and III CC patients, but only modestly increases prediction accuracy in multivariable models that include clinicopathological features, particularly in chemotherapy-treated patients.

Background\ud Somatic mutations in the epidermal growth factor receptor (EGFR) intracellular signalling pathways predict non-response to cetuximab in the treatment of advanced colorectal cancer (aCRC). We hypothesized that common germline variants within these pathways may also play similar roles.\ud \ud Methods\ud We analysed 54 potentially functional, common, inherited EGFR pathway variants in 815 aCRC patients treated with oxaliplatin-fluoropyrimidine chemotherapy +cetuximab. Primary endpoints were response and skin rash (SR). We had >85% power to detect ORs=1.6 for variants with minor allele frequencies >20%.\ud \ud Results\ud We identified five potential biomarkers for response and four for SR, although none remained significant after correction for multiple testing. Our initial data supported a role for Ser313Pro in PIK3R2 in modulating response to cetuximab - in patients with KRAS wild type CRCs, 36.4% of patients with one allele encoding proline responded, as compared to 71.2% of patients homozygous for alleles encoding serine (OR 0.23, 95% CI 0.09-0.56, P=0.0014) and this association was predictive for cetuximab (Pinteraction=0.017); however, independent replication failed to validate this association. No previously proposed predictive biomarkers were validated.\ud \ud Conclusions\ud Our study highlights the need to validate potential pharmacogenetic biomarkers. We did not find strong evidence for common germline biomarkers of cetuximab response and toxicity.

Background and study aims (Virtual) chromoendoscopy detects more polyps than standard white-light endoscopy in patients with Lynch syndrome. Previous back-to-back trials did not randomize for the examination order, creating a possible bias in favor of chromoendoscopy. We aimed to assess the difference in polyp detection between high definition white-light endoscopy (HD-WLE) and virtual chromoendoscopy with I-SCAN in patients with Lynch syndrome. Patients and methods In this prospective, controlled trial, patients were randomized to either HD-WLE followed by I-SCAN (Group 1; n = 31) or I-SCAN followed by HD-WLE (Group 2; n = 30). Polyps found during the first pass were removed. The primary end point of the study was the difference in adenoma detection between HD-WLE and I-SCAN, expressed as the miss rate for adenomas for each technique. Results In Group 1, I-SCAN detected four additional patients with at least one adenoma, whereas HD-WLE did not increase the adenoma detection rate in Group 2 (relative risk [RR] 0.4; P = 0.08). In Group 1, five adenomas were detected and removed with HD-WLE and a second pass with I-SCAN detected a further eight adenomas. In Group 2, I-SCAN detected 15 adenomas and subsequent HD-WLE detected 2 additional adenomas. The adenoma miss rate was significantly higher for HD-WLE (62 %) compared with I-SCAN (12 %; RR 0.44, 95 % confidence interval [CI] 0.21 to 0.87; P = 0.007). The miss rate for lesions was 57 % and 24 %, respectively, and was significantly different in favor of I-SCAN (RR 0.54, 95 %CI 0.3 to 0.85; P = 0.005). The mean inspection time in both groups was not significantly different during first (485 vs. 536 seconds; 95 %CI – 139.91 to 33.34) or second pass (421 vs. 387 seconds; 95 %CI – 32.24 to 104.89). Conclusion Our data suggest that virtual chromoendoscopy with I-SCAN reduces the adenoma and polyp miss rate in patients with Lynch syndrome, independently of inspection time. Trial registration: ClinicalTrials.gov (NCT01823471).

Background ALK, ROS1, and NTRK fusions occur in 0.2% to 2.4% of colorectal cancers. Pioneer cases of metastatic colorectal cancer (mCRC) patients bearing rearrangements who benefited from anti-ALK, ROS, and TrkA-B-C therapies have been reported previously. Here we aimed at characterizing the clinical and molecular landscape of ALK, ROS1, and NTRK rearranged mCRC. Methods Clinical features and molecular characteristics of 27 mCRC patients bearing ALK, ROS1, and NTRK rearranged tumors were compared with those of a cohort of 319 patients not bearing rearrangements by means of Fisher's exact, χ2 test, or Mann-Whitney test as appropriate. Overall survival curves were estimated with the Kaplan-Meier method and compared using the log-rank test. A Cox proportional hazard model was adopted in the multivariable analysis. Deep molecular and immunophenotypic characterizations of rearranged cases, including those described in The Cancer Genome Atlas database, were performed. All statistical tests were two-sided. Results Closely recalling the "BRAF history," ALK, ROS1, and NTRK rearrangements more frequently occurred in elderly patients (P = .02) with right-sided tumors (P < .001) and node-spreading (P = .03), RAS wild-type (P < .001), and MSI-high (P < .001) cancers. All patients bearing ALK, ROS1, and NTRK fusions had shorter overall survival (15.6 months, 95% confidence interval [CI] = 0.0 to 20.4 months) than negative patients (33.7 months, 95% CI = 28.3 to 42.1 months), both in the univariate (hazard ratio [HR] = 2.17, 95% CI = 1.03 to 4.57, P < .001) and multivariable models (HR = 2.33, 95% CI = 1.10 to 4.95, P = .02). All four evaluable patients with rearrangements showed primary resistance to anti-epidermal growth factor receptor agents. Frequent association with potentially targetable RNF43 mutations was observed in MSI-high rearranged tumors. Conclusions ALK, ROS1, and NTRK rearrangements define a new rare subtype of mCRC with extremely poor prognosis. Primary tumor site, MSI-high, and RAS and BRAF wild-type status may help to identify patients bearing these alterations. While sensitivity to available treatments is limited, targeted strategies inhibiting ALK, ROS, and TrkA-B-C provided encouraging results.

The increasing number of drugs targeting specific proteins implicated in tumourigenesis and the commercial promotion of relatively affordable genome-wide analyses has led to an increasing expectation among patients with cancer that they can now receive effective personalised treatment based on the often complex genomic signature of their tumour. For such approaches to work in routine practice, the development of correspondingly complex biomarker assays through an appropriate and rigorous regulatory framework will be required. It is becoming increasingly evident that a re-engineering of clinical research is necessary so that regulatory considerations and procedures facilitate the efficient translation of these required biomarker assays from the discovery setting through to clinical application. This article discusses the practical requirements and challenges of developing such new precision medicine strategies, based on leveraging complex genomic profiles, as discussed at the Innovation and Biomarkers in Cancer Drug Development meeting (8th-9th September 2016, Brussels, Belgium).

Inappropriate activation of epidermal growth factor receptor (EGFR) plays a causal role in many cancers including colon cancer. The activation of EGFR by phosphorylation is balanced by receptor kinase and protein tyrosine phosphatase activities. However, the mechanisms of negative EGFR regulation by tyrosine phosphatases remain largely unexplored. Our previous results indicate that protein tyrosine phosphatase receptor type O (PTPRO) is down-regulated in a subset of colorectal cancer (CRC) patients with a poor prognosis. Here we identified PTPRO as a phosphatase that negatively regulates SRC by directly dephosphorylating Y416 phosphorylation site. SRC activation triggered by PTPRO down-regulation induces phosphorylation of both EGFR at Y845 and the c-CBL ubiquitin ligase at Y731. Increased EGFR phosphorylation at Y845 promotes its receptor activity, whereas enhanced phosphorylation of c-CBL triggers its degradation promoting EGFR stability. Importantly, hyperactivation of SRC/EGFR signaling triggered by loss of PTPRO leads to high resistance of colon cancer to EGFR inhibitors. Our results not only highlight the PTPRO contribution in negative regulation of SRC/EGFR signaling but also suggest that tumors with low PTPRO expression may be therapeutically targetable by anti-SRC therapies.

Treatment options for colorectal cancer have increased substantially in the past decade, with the introduction of novel biological therapies targeting cancer-specific molecules leading to significantly improved outcomes. Despite access to these treatments, we are not yet in an era where we can fully personalize treatment choices for patients with colorectal cancer. A number of prognostic and predictive markers have been identified that appear to be directly related to sensitivity to targeted therapies, such as those against epidermal growth factor receptor. However, the sensitivities of individual tumors toward different biological agents appear to be more complex. It seems that a more complete molecular signature of the tumor must be taken into account when making individual treatment choices. In the absence of having fully elucidated the influence of these prognostic or predictive markers, other surrogate markers of early treatment success may be useful in determining whether to continue treatment with a particular agent. In this review, we discuss the role of molecular markers in choosing appropriate treatment for the individual patient, along with the use of measuring the depth of response to a particular agent to assist decisions on whether to continue therapy in colorectal cancer.

// Albert Bosch-Vilaro 1, * , Bart Jacobs 1, * , Valentina Pomella 1 , Layka Abbasi Asbagh 1 , Richard Kirkland 2 , Joe Michel 2 , Sharat Singh 2 , Xinjun Liu 2 , Phillip Kim 2 , Gregory Weitsman 3 , Paul R Barber 4 , Borivoj Vojnovic 3, 4 , Tony Ng 3, 5, 6 , Sabine Tejpar 1 1 Laboratory of Molecular Digestive Oncology, Department of Oncology, KU Leuven, Leuven, Belgium 2 Prometheus Laboratories, San Diego, CA, USA 3 Richard Dimbleby Department of Cancer Research, Randall Division & Division of Cancer Studies, King’s College London, Guy’s Medical School Campus, London, UK 4 Department of Oncology, Cancer Research UK and Medical Research Council Oxford Institute for Radiation Oncology, University of Oxford, Oxford, UK 5 Breast Cancer Now Research Unit, King’s College London, London, UK 6 UCL Cancer Institute, Paul O'Gorman Building, University College London, London, UK * These authors contributed equally to this work Correspondence to: Sabine Tejpar, email: sabine.tejpar@uzleuven.be Keywords: colorectal cancer, cetuximab resistance, HER3, dimerization, feedback loop Received: September 14, 2016 Accepted: November 30, 2016 Published: December 09, 2016 ABSTRACT The EGFR inhibitor cetuximab is approved for the treatment of colorectal cancer. However, both innate and acquired resistance mechanisms, including compensatory feedback loops, limit its efficacy. Nevertheless, the emergence of these feedback loops has remained largely unexplored to date. Here, we showed feedback upregulation of HER3 and induction of HER3 phosphorylation after cetuximab treatment in colon cancer cells. We also showed that this upregulation occurs, at least partly, through AKT inhibition. Together with this, we observed increased HER2:HER3 dimerization upon cetuximab treatment. Interestingly, lapatinib, a dual EGFR and HER2 tyrosine kinase inhibitor, blocked the increase of cetuximab-induced HER3 phosphorylation. Additionally, we showed that upon HER3 knockdown, cetuximab combined with lapatinib was able to decrease cell viability compared to HER3 expressing cells. These results suggest the existence of a cetuximab-induced feedback HER3 activation that could potentially result in reduced cetuximab efficacy in colorectal cancer patients. Taken together, we provide evidence of the limited effectiveness of cetuximab monotherapy compared to rational combinations.

The availability of targeted anticancer drugs and the relative affordability of genomic analyses has led to a growing expectation among patients with cancer that they can receive personalized treatment based on the genomic signature of their tumour. Here, we discuss some of the challenges and steps needed to bring such approaches into routine practice.

Immunotherapy for patients with non-highly mutated, mismatch repair-proficient (MMRprof) metastatic colorectal cancer has largely been unsuccessful thus far. Here, we used transcriptomics, genomics and in vitro analyses to study the adaptive immune features of colorectal cancer liver metastases (CRLMs), aiming to provide insights into the development of immunotherapies for this common malignancy. Analysis of the RNAseq data from 63 core biopsies obtained in patients enrolled in the Q-CROC-01 trial (NCT00984048) revealed 17 (27%) immune-reactive (IR) CRLMs, defined by concurrent relative high expression of antigen processing, immune cell, immune checkpoint, interferon-gamma response, cytokine, and chemokine transcripts. More T-cell receptor (TCR) sequences were found in IR vs. non-IR CRLMs (mean 89.8 ± 13.3 vs. 19.5 ± 4.0 CDR3 counts, p Our results support that naturally occurring neoAg-reactive T cells may be therapeutically harnessed in a subgroup of metastatic MMRprof colorectal cancer patients selected based on the level of intratumoral immune reactivity, and potentially enhanced by targeting immune checkpoints more biologically relevant than PD-1/PD-L1 and CTLA-4/CD80. Citation Format: Steven Hébert, Mélissa Mathieu, David Henault, Maud Marques, Éric Audemard, Mathieu Courcelles, Scott D. Brown, Pratyaksha Wirapati, Sabine Tejpar, Michael I. D'Angelica, Robert A. Holt, Sylvie Mader, Pierre Thibault, Gerald Batist, Claudia Kleinman, Simon Turcotte. Immune features and neoantigen recognition in mismatch repair-proficient colorectal cancer liver metastases [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 579.

BACKGROUND AND AIMS: Colorectal cancer is an epigenetically heterogeneous disease, however the extent and spectrum of the CpG Island Methylator Phenotype (CIMP) is not clear.METHODS: Genome scale methylation and transcript expression were measured using the Illumina HM450 DNA methylation and HT12 V3 expression microarrays in 216 unselected colorectal cancers. Mutations in epigenetic regulators were assessed using CIMP-classified Cancer Genome Atlas exomes.RESULTS: CIMP-High cancers dichotomised into CIMP-H1 and CIMP-H2 based on methylation profile, which was supported by over-representation of BRAF (74%, P Citation Format: Vicki L. Whitehall, Lochlan Fennell, Troy Dumenil, Gunter Hartel, Katia Nones, Catherine Bond, Diane McKeone, Ann-Marie Patch, Stephen Kazakoff, John Pearson, Nicola Waddell, Pratyaksha Wirapati, Paul Lochead, Shuji Ogino, Sabine Tejpar, Barbara Leggett. BRAF and KRAS mutation define distinct subtypes of the CpG island methylator phenotype in colorectal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 479.

3601 Background: High stromal content (CMS4) and immune infiltration (CMS1) are important features of the tumor micro-environment (TME) in early stage colorectal cancer, with poor and good RFS prognosis, respectively. However, it remains unclear how these TME features are influenced by intrinsic tumor epithelial expression profiles. We examined how the former can be predicted by the latter, and assessed their respective prognostic contributions. Methods: Eighteen public gene-expression datasets (n=3511) were used for discovery, and an adjuvant trial dataset (PETACC3 n=688) was used for validation. Whole-transcriptome hierarchical clustering was applied to identify intrinsic versus extrinsic co-expression modules, corroborated by single-cell profiling data. The epithelial gene subset were used to predict previously assigned CMS labels, producing new CRC classifier that we refer to as epithelial-CMS (eCMS). Results: Despite lacking stromal and immune response genes, eCMS predicted CMS with an accuracy of 82% [CI 78-85%] in the test dataset. Not only were the RFS prognostic values retained (eCMS1 vs non-eCMS1: HR=0.59 [CI 0.35–0.95, p=0.029], and eCMS4 vs non-e-CMS4: HR=1.82 [CI 1.38–2.41, p=0.0003]), but they were also significantly improved when compared to the original CMS classification (CMS1 vs non-CMS1: HR=0.76 [CI 0.49–1.16, p=0.2] and CMS4 vs non-CMS4: HR=1.43 [CI 1.07–1.91, p=0.017]. In a multivariable regression comparison, eCMS was superior to CMS (p=0.001 vs p=0.36). Each eCMS group was associated with specific combinations of up- and down-regulation of CRC-relevant pathways, such as CDX2, map-kinase, mucin secretion, DNA damage repair and cell proliferation. Conclusions: Stromal and immune infiltration patterns in the TME are strongly associated with tumor epithelial expression profiles, as captured by eCMS. This finding sheds new light on the interplay between intrinsic molecular features of CRCs and their TME, and illuminates new paths for potential combination therapies.

The majority of samples in existing tumour biobanks are surgical specimens of primary tumours. Insights into tumour biology, such as intratumoural heterogeneity, tumour-host crosstalk, and the evolution of the disease during therapy, require biospecimens from the primary tumour and those that reflect the patient's disease in specific contexts. Next-generation 'omics' technologies facilitate deep interrogation of tumours, but the characteristics of the samples can determine the ultimate accuracy of the results. The challenge is to biopsy tumours, in some cases serially over time, ensuring that the samples are representative, viable, and adequate both in quantity and quality for subsequent molecular applications. The collection of next-generation biospecimens, tumours, and blood samples at defined time points during the disease trajectory--either for discovery research or to guide clinical decisions--presents additional challenges and opportunities. From an organizational perspective, it also requires new additions to the multidisciplinary therapeutic team, notably interventional radiologists, molecular pathologists, and bioinformaticians. In this Review, we describe the existing procedures for sample procurement and processing of next-generation biospecimens, and highlight the issues involved in this endeavour, including the ethical, logistical, scientific, informational, and financial challenges accompanying next-generation biobanking.

The RAS/RAF/MEK/MAPK and the PTEN/PI3K/AKT/mTOR pathways are key regulators of proliferation and survival in human cancer cells. Selective inhibitors of different transducer molecules in these pathways have been developed as molecular targeted anti-cancer therapies. The in vitro and in vivo anti-tumor activity of pimasertib, a selective MEK 1/2 inhibitor, alone or in combination with a PI3K inhibitor (PI3Ki), a mTOR inhibitor (everolimus), or with multi-targeted kinase inhibitors (sorafenib and regorafenib), that block also BRAF and CRAF, were tested in a panel of eight human lung and colon cancer cell lines. Following pimasertib treatment, cancer cell lines were classified as pimasertib-sensitive (IC50 for cell growth inhibition of 0.001 µM) or pimasertib-resistant. Evaluation of basal gene expression profiles by microarrays identified several genes that were up-regulated in pimasertib-resistant cancer cells and that were involved in both RAS/RAF/MEK/MAPK and PTEN/PI3K/AKT/mTOR pathways. Therefore, a series of combination experiments with pimasertib and either PI3Ki, everolimus, sorafenib or regorafenib were conducted, demonstrating a synergistic effect in cell growth inhibition and induction of apoptosis with sustained blockade in MAPK- and AKT-dependent signaling pathways in pimasertib-resistant human colon carcinoma (HCT15) and lung adenocarcinoma (H1975) cells. Finally, in nude mice bearing established HCT15 and H1975 subcutaneous tumor xenografts, the combined treatment with pimasertib and BEZ235 (a dual PI3K/mTOR inhibitor) or with sorafenib caused significant tumor growth delays and increase in mice survival as compared to single agent treatment. These results suggest that dual blockade of MAPK and PI3K pathways could overcome intrinsic resistance to MEK inhibition.

Purpose: BRAFV600E mutations are associated with poor clinical prognosis in colorectal cancer (CRC). Although selective BRAF inhibitors are effective for treatment of melanoma, comparable efforts in CRC have been disappointing. Here, we investigated potential mechanisms underlying this resistance to BRAF inhibitors in BRAFV600E CRC. Experimental Design: We examined phosphoinositide 3-kinase (PI3K)/mTOR signaling in BRAFV600E CRC cell lines after BRAF inhibition and cell viability and apoptosis after combined BRAF and PI3K/mTOR inhibition. We assessed the efficacy of in vivo combination treatment using a novel genetically engineered mouse model (GEMM) for BRAFV600E CRC. Results: Western blot analysis revealed sustained PI3K/mTOR signaling upon BRAF inhibition. Our BRAFV600E GEMM presented with sessile serrated adenomas/polyps, as seen in humans. Combination treatment in vivo resulted in induction of apoptosis and tumor regression. Conclusions: We have established a novel GEMM to interrogate BRAFV600E CRC biology and identify more efficacious treatment strategies. Combination BRAF and PI3K/mTOR inhibitor treatment should be explored in clinical trials. Clin Cancer Res; 19(10); 2688–98. ©2013 AACR.

Purpose: This randomized, double-blind, placebo-controlled, phase IIb study evaluated adding sorafenib to first-line modified FOLFOX6 (mFOLFOX6) for metastatic colorectal cancer (mCRC). Experimental Design: Patients were randomized to sorafenib (400 mg b.i.d.) or placebo, combined with mFOLFOX6 (oxaliplatin 85 mg/m2; levo-leucovorin 200 mg/m2; fluorouracil 400 mg/m2 bolus and 2400 mg/m2 continuous infusion) every 14 days. Primary endpoint was progression-free survival (PFS). Target sample was 120 events in 180 patients for >85% power (two-sided α = 0.20) to detect an HR = 0.65. Results: Of 198 patients randomized, median PFS for sorafenib plus mFOLFOX6 was 9.1 months versus 8.7 months for placebo plus mFOLFOX6 (HR = 0.88; 95% CI, 0.64–1.23; P = 0.46). There was no difference between treatment arms for overall survival. Subgroup analyses of PFS and overall survival showed no difference between treatment arms by KRAS or BRAF status (mutant and wild type). The most common grade 3/4 adverse events in the sorafenib and placebo arms were neutropenia (48% vs. 22%), peripheral neuropathy (16% vs. 21%), and grade 3 hand–foot skin reaction (20% vs. 0%). Treatment discontinuation because of adverse events was 9% and 6%, respectively. Generally, dose intensity (duration and cumulative doses) was lower in the sorafenib arm than in the placebo arm. Conclusion: This study did not detect a PFS benefit with the addition of sorafenib to first-line mFOLFOX6 for mCRC. KRAS and BRAF status did not seem to impact treatment outcomes but the subgroups were small. These results do not support further development of sorafenib in combination with mFOLFOX6 in molecularly unselected patients with mCRC. Clin Cancer Res; 19(9); 2541–50. ©2013 AACR.