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Upfront KRAS and NRAS gene testing ('RAS') is the standard of care for metastatic colorectal cancer (mCRC), to guide first-line treatment. The presence of RAS mutation (MT) is a negative predictor for the efficacy of anti-EGFR antibodies and the use of cetuximab and panitumumab is restricted to RAS wild-type (WT) mCRC. Conversion from RAS WT to RAS MT mCRC after treatment with anti-EGFR antibodies is a known and well-described acquired resistance mechanism. The by far less frequent 'NeoRAS wild-type' phenomenon (reversion from RAS MT to RAS WT) has recently drawn attention. The proposed effect of chemotherapy on RAS status in mCRC patients is not fully understood. Because of the intriguing biological consequence of a RAS MT to RAS WT reversion, subsequent treatment of NeoRAS WT patients with anti-EGFR antibodies is increasingly being discussed. Here, we report three clinical cases of NeoRAS WT mCRC patients, which received standard-of-care regimens for RAS MT mCRC. Anti-EGFR antibodies were used in two out of three patients after progression of the disease. One of the patients had a long-term response. In line with our observations, NeoRAS WT phenomenon occurs in clinical practice. Retesting of RAS status during treatment should be discussed in patients with unusual long-term clinical courses of RAS MT mCRC to optimise treatment strategy and to evaluate the use of anti-EGFR antibodies., Competing Interests: Conflicts of interest statement L.V. received research funding from Pierre Fabre, participant in the Charité-BIH Clinician Scientist Program funded by the Charité Universitätsmedizin Berlin and Berlin Institute of Health. L.V. spouse is an employee and shareholder of Bayer AG. U.K. received honoraria from AstraZeneca, Bayer Schering Pharma, Bristol-Myers Squibb, Glycotope GmbH, Merck KGaA, MSD Oncology, Novartis, Pfizer, Roche/Genentech; consulting or advisory role for AstraZeneca, Bristol-Myers Squibb, Merck Serono, MSD Oncology, Pfizer; speakers' bureau for AstraZeneca, Bayer Schering Pharma, Bristol-Myers Squibb, Merck Serono, MSD Oncology, Novartis; and received research funding from AstraZeneca/MedImmune (Inst), Pfizer (Inst), Travel, Accommodations, Expenses: AstraZeneca, Bayer Schering Pharma, Ipsen, Merck Serono, MSD Oncology, Pierre Fabre. A.H.S.A. consulting or advisory role for Roche and received travel, accommodations, expenses from Pfizer, Roche, Eli Lilly, Novartis, PharmaMar. J.C.v.E. received honoraria from Merck, Roche, Amgen, Sanofi, Pierre Fabre, Servier, Taiho, BMS, Eisai, Novartis; consulting or advisory role for Amgen, Pierre Fabre, BMS, Servier; travel, accommodations, expenses: AstraZeneca, Apceth. A.S. received honoraria from Roche, Servier; travel, accommodations, expenses from Roche, Merck KgA, MSD Sharp & Dohme, Pfizer, Amgen. A.K. received honoraria from Taiho Pharmaceutical, Servier; travel, accommodations, expenses: Roche, Medac. D.P.M. received honoraria from Amgen, Bristol-Myers Squibb, Merck Serono, Merck Sharp & Dohme, Pfizer, Roche, Servier, Taiho Pharmaceutical; consulting or advisory role: Amgen, Merck Serono, Merck Sharp & Dohme, Roche, Servier; received research funding from Amgen (Inst), Merck Serono (Inst), Roche (Inst); travel, accommodations, expenses: Amgen, Bayer, Bristol-Myers Squibb, Merck Serono, Roche, Servier. S.S. received honoraria Amgen, Bayer, Lilly, Merck KGaA, Pierre Fabre, Roche, Sanofi, Servier, Sirtex Medical, Taiho Pharmaceutical, Takeda; consulting or advisory role: Amgen, Bayer, Boehringer Ingelheim, Lilly, Merck KGaA, MSD, Pierre Fabre, Roche; Sanofi, Servier, Takeda; research funding: Merck Serono (Inst), Pierre Fabre (Inst), Roche Molecular Diagnostics (Inst); travel, accommodations, expenses: Amgen, Bayer, Lilly, Merck KGaA, Pierre Fabre, Roche, Sanofi, Sirtex Medical, Takeda. I.J. received honoraria from Bristol-Myers Squibb, Roche. All remaining authors have declared no conflicts of interest., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Since metastatic colorectal cancer (CRC) is a leading cause of cancer-related death, therapeutic approaches overcoming primary and acquired therapy resistance are an urgent medical need. In this study, the efficacy and toxicity of high-affinity inhibitors targeting antiapoptotic BCL-2 proteins (BCL-2, BCL-XL, and MCL-1) were evaluated. By RNA sequencing analysis of a pan-cancer cohort comprising >1500 patients and subsequent prediction of protein activity, BCL-XL was identified as the only antiapoptotic BCL-2 protein that is overactivated in CRC. Consistently, pharmacologic and genetic inhibition of BCL-XL induced apoptosis in human CRC cell lines. In a combined treatment approach, targeting BCL-XL augmented the efficacy of chemotherapy in vitro, in a murine CRC model, and in human ex vivo derived CRC tissue cultures. Collectively, these data show that targeting of BCL-XL is efficient and safe in preclinical CRC models, observations that pave the way for clinical translation.

To date, no systematic analyses are available assessing concordance of molecular classifications between primary tumors (PT) and matched liver metastases (LM) of metastatic colorectal cancer (mCRC). We investigated concordance between PT and LM for four clinically relevant CRC gene signatures. Twenty-seven fresh and 55 formalin-fixed paraffin-embedded pairs of PT and synchronous LM of untreated mCRC patients were retrospectively collected and classified according to the MSI-like, BRAF-like, TGFB activated-like and the Consensus Molecular Subtypes (CMS) classification. We investigated classification concordance between PT and LM and association of TGFBa-like and CMS classification with overall survival. Fifty-one successfully profiled matched pairs were used for analyses. PT and matched LM were highly concordant in terms of BRAF-like and MSI-like signatures, (90.2% and 98% concordance, respectively). In contrast, 40% to 70% of PT that were classified as mesenchymal-like, based on the CMS and the TGFBa-like signature, respectively, lost this phenotype in their matched LM (60.8% and 76.5% concordance, respectively). This molecular switch was independent of the microenvironment composition. In addition, the significant change in subtypes was observed also by using methods developed to detect cancer cell-intrinsic subtypes. More importantly, the molecular switch did not influence the survival. PT classified as mesenchymal had worse survival as compared to nonmesenchymal PT (CMS4 vs CMS2, hazard ratio [HR] = 5.2, 95% CI = 1.5-18.5, P = .0048; TGFBa-like vs TGFBi-like, HR = 2.5, 95% CI = 1.1-5.6, P = .028). The same was not true for LM. Our study highlights that the origin of the tissue may have major consequences for precision medicine in mCRC., (© 2020 The Authors. International Journal of Cancer published by John Wiley & Sons Ltd on behalf of UICC.)

COVID-19 pandemic challenges health system capacities in many countries. National healthcare services have to manage unexpected shortage of healthcare resources that have to be reallocated according to the principles of fair and ethical prioritisation, in order to maintain the highest levels of care to all patients, ensure the safety of patients and healthcare workers and save as many lives as possible. Beyond that, cancer care services have to pursue restructuring, following the same evidence-based dispositions. In this article, we propose guidance to the management of colorectal cancer during the pandemic, prioritised according to a three-tiered framework, based on expert clinical judgement and magnitude of benefit expected from specific interventions. Since the availability of resources for diagnostic procedures, surgery and postoperative care, systemic therapy and radiotherapy may differ, authors did separate prioritisation analyses. The impact of postponing or abrogating cancer interventions on outcomes according to a high, medium or low priority scale, is outlined and discussed. The implementation of healthcare services using telemedicine is explored: it reveals itself as functional and effective for limiting patients' need to travel to centres and thereby has the potential to reduce diffusion of severe acute respiratory syndrome coronavirus 2. Colorectal cancer demands a considerable amount of medical resources. Therefore, the redefinition of its diagnostic and therapeutic algorithms with a rigorous method is crucial in order to ensure the highest quality of continuum of care in the broader context of the pandemic and the challenged healthcare systems., Competing Interests: Competing interests: LV is a member of the GI connect group, spouse is employee and shareholder of Bayer AG. LV reported grants for translational research from Pierre Fabre und is participant in the Charité-BIH Clinician Scientist Program funded by the Charité Universitaetsmedizin Berlin und Berlin Institute of Health. SS: personal fees from Amgen, Bayer, Isofol, Lilly, Merck KGaA, MSD, Nordic Pharma, Pierre-Fabre, Roche, Sanofi, Sirtex, Servier, Takeda, Taiho, research grants from Pierre-Fabre, Merck KGaA, Roche. GP: Research grants from Amgen, AstraZeneca, Roche, MSD, BMS, Merck, outside of the submitted work. FL: personal fees from Amgen, Astellas, AstraZeneca, Biontech, Eli Lilly, Elsevier, Excerpta Medica, Imedex, Infomedica, Medscape, MedUpdate, Merck Serono, Merck Sharp & Dohme, Oncovis, Promedicis, Springer Nature, StreamedUp!, and Zymeworks; and research grants and personal fees from Bristol-Myers Squibb and Iomedico, outside the submitted work., (© Author (s) (or their employer(s)) 2020. Re-use permitted under CC BY-NC. No commercial re-use. Published by BMJ on behalf of the European Society for Medical Oncology.)

Objective: We aimed to better clarify the role of germline variants of the FCG2 receptor, FCGR2A-H131R and FCGR3A-V158F, on the therapeutic efficacy of cetuximab in metastatic colorectal cancer (mCRC). A large cohort with sufficient statistical power was assembled., Design: To show a HR advantage of 0.6 in progression-free survival (PFS) for FCGR2A-HH versus the rest and FCGR3A-VV versus the rest, with an 80% power, 80 Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) wild-type (KRAS-WT) and 52 KRAS-WT patients are required, respectively. This leads to a total sample size of 952 and 619 patients, respectively. Samples were collected from 1123 mCRC patients from 15 European centres treated with cetuximab alone or in combination with chemotherapy. Fc gamma receptor (FCGR) status was centrally genotyped. Two additional externally genotyped series were included., Results: Incidences of FCGR2A-HH and FCGR3A-VV in KRAS-WT patients were 220/660 (33%) and 109/676 (16.1%) respectively. There was no difference in median PFS (mPFS) for KRAS-WT patients with FCGR2A-HH (22.0 weeks; 95% CI18.8 to 25.2) versus non-HH (22.0 weeks; 95% CI 19.4 to 24.6) or for FCGR3A-VV (16.4 weeks; 95% CI 13.0 to 19.8) versus non-VV (23 weeks; 95% CI 21.1 to 24.9) (p=0.06). Median overall survival, response rate and disease control rate assessments showed no benefit for either HH or VV., Conclusions: No differences in mPFS were found between the FCGR polymorphisms HH and the others and VV versus the others in KRAS-WT mCRC patients refractory to irinotecan, oxaliplatin and 5-fluorouracil treated with cetuximab. We cannot confirm the effects of other IgG1 antibodies, which may be weaker than previously suggested. Other markers may be needed to study the actual host antibody response to cetuximab., (Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.)

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., (Copyright © 2013 UICC.)

As dual-specificity phosphatase (DUSP) expression has been correlated to sensitivity to MEK inhibitors, DUSP expression levels may indicate activation of the mitogen-activated protein kinase (MAPK) pathway in many tumor types. In this study, we investigate if DUSP levels can indicate different levels of MAPK activation within colorectal cancer (CRC) patients. In three different CRC patient microarray datasets, we analyzed the expression of DUSP1. DUSP4 and DUSP6 according to mutational status, their correlation with survival and their association with different clinical characteristics. DUSP4 was significantly differentially expressed between all mutational subgroups with the highest expression in BRAF mutated tumors. Moreover, high DUSP4 expression was associated with a worse overall survival and with clinical characteristics typical for BRAF mutant patients. The use of DUSP expression as a predictive biomarker towards MAPK targeted therapy in CRC patients needs further investigation.

Despite a decrease in incidence and mortality, colorectal cancer (CRC) still represents the second leading cause of cancer worldwide. Recurrence following surgery and adjuvant treatment and the metastatic disease are still a major problem with a median overall survival of approximately 24 months. Nevertheless, there has been an improvement in outcome due to the introduction into clinical practice of new cytotoxic and targeted agents. The targeted agents that have improved the efficacy of the available chemotherapeutic regimens in CRC are the ones that target the vascular endothelial growth factor (VEGF) and the epidermal growth factor receptor (EGFR). In particular, bevacizumab, a recombinant humanized monoclonal antibody against VEGF, cetuximab, and panitumumab, two monoclonal antibodies that target the EGFR, have been approved for the treatment of metastatic CRC (mCRC). While for anti-EGFR agents, predictive biomarkers have been found, no good biomarkers have been found yet for anti-VEGF agents. Aflibercept and regorafenib have recently also been approved in patients with mCRC. This article reviews in an extensive way the data of large randomized clinical trials for the use of anti-VEGF and anti-EGFR in CRC. Aim of this review is also to describe the current status of biomarkers discovery and highlight how to improve the therapeutic index of these targeted agents by selecting in advance the subgroup of patients who will benefit from these treatments.

Purpose: BRAF(V600E) 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 BRAF(V600E) CRC., Experimental Design: We examined phosphoinositide 3-kinase (PI3K)/mTOR signaling in BRAF(V600E) 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 BRAF(V600E) CRC., Results: Western blot analysis revealed sustained PI3K/mTOR signaling upon BRAF inhibition. Our BRAF(V600E) 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 BRAF(V600E) CRC biology and identify more efficacious treatment strategies. Combination BRAF and PI3K/mTOR inhibitor treatment should be explored in clinical trials., (©2013 AACR)

Purpose: Cancer cell survival, invasion, and metastasis depend on cancer cell proliferation and on tumor-induced angiogenesis. We evaluated the efficacy of the combination of sorafenib and erlotinib or cetuximab., Experimental Design: Sorafenib, erlotinib, and cetuximab, alone or in combination, were tested in vitro in a panel of non-small cell lung cancer (NSCLC) and colorectal cancer cell lines and in vivo in H1299 tumor xenografts., Results: Epidermal growth factor receptor (EGFR) ligand mRNAs were expressed in all NSCLC and colorectal cancer cell lines with variable levels ranging from 0.4- to 8.1-fold as compared with GEO colorectal cancer cells. Lung cancer cells had the highest levels of vascular endothelial growth factors (VEGF) A, B, and C, and of VEGF receptors as compared with colorectal cancer cells. Combined treatments of sorafenib with erlotinib or cetuximab produced combination index values between 0.02 and 0.5, suggesting a significant synergistic activity to inhibit soft agar colony formation in all cancer cell lines, which was accompanied by a marked blockade in mitogen-activated protein kinase and AKT signals. The in vitro migration of H1299 cells, which expressed high levels of both VEGF ligands and receptors, was inhibited by treatment with sorafenib, and this effect was significantly increased by the combination with anti-EGFR drugs. In nude mice bearing established human H1299 xenografts, treatment with the combination of sorafenib and erlotinib or cetuximab caused a significant tumor growth delay resulting in 70 to 90 days increase in mice median overall survival as compared with single-agent sorafenib treatment., Conclusions: Combination treatment with sorafenib and erlotinib or cetuximab has synergistic antitumor effects in human colorectal and lung cancer cells.