Machine Learning Predicts Oxaliplatin Benefit in Early Colon Cancer.

PURPOSE: A combination of fluorouracil, leucovorin, and oxaliplatin (FOLFOX) is the standard for adjuvant therapy of resected early-stage colon cancer (CC). Oxaliplatin leads to lasting and disabling neurotoxicity. Reserving the regimen for patients who benefit from oxaliplatin would maximize efficacy and minimize unnecessary adverse side effects. METHODS: We trained a new machine learning model, referred to as the colon oxaliplatin signature (COLOXIS) model, for predicting response to oxaliplatin-containing regimens. We examined whether COLOXIS was predictive of oxaliplatin benefits in the CC adjuvant setting among 1,065 patients treated with 5-fluorouracil plus leucovorin (FULV; n = 421) or FULV + oxaliplatin (FOLFOX; n = 644) from NSABP C-07 and C-08 phase III trials. The COLOXIS model dichotomizes patients into COLOXIS+ (oxaliplatin responder) and COLOXIS- (nonresponder) groups. Eight-year recurrence-free survival was used to evaluate oxaliplatin benefits within each of the groups, and the predictive value of the COLOXIS model was assessed using the P value associated with the interaction term (int P) between the model prediction and the treatment effect. RESULTS: Among 1,065 patients, 526 were predicted as COLOXIS+ and 539 as COLOXIS-. The COLOXIS+ prediction was associated with prognosis for FULV-treated patients (hazard ratio [HR], 1.52 [95% CI, 1.07 to 2.15]; P = .017). The model was predictive of oxaliplatin benefits: COLOXIS+ patients benefited from oxaliplatin (HR, 0.65 [95% CI, 0.48 to 0.89]; P = .0065; int P = .03), but COLOXIS- patients did not (COLOXIS- HR, 1.08 [95% CI, 0.77 to 1.52]; P = .65). CONCLUSION: The COLOXIS model is predictive of oxaliplatin benefits in the CC adjuvant setting. The results provide evidence supporting a change in CC adjuvant therapy: reserve oxaliplatin only for COLOXIS+ patients, but further investigation is warranted.

Neratinib-Plus-Cetuximab in Quadruple-WT (KRAS, NRAS, BRAF, PIK3CA) Metastatic Colorectal Cancer Resistant to Cetuximab or Panitumumab: NSABP FC-7, A Phase Ib Study.

PURPOSE: In metastatic colorectal cancer (mCRC), HER2 (ERBB2) gene amplification is implicated in anti-EGFR therapy resistance. We sought to determine the recommended phase II dose (RP2D) and efficacy of neratinib, a pan-ERBB kinase inhibitor, combined with cetuximab, in patients with progressive disease (PD) on anti-EGFR treatment. PATIENTS AND METHODS: Twenty-one patients with quadruple-wild-type, refractory mCRC enrolled in this 3+3 phase Ib study. Standard dosage cetuximab was administered with neratinib at 120 mg, 160 mg, 200 mg, and 240 mg/day orally in 28-day cycles. Samples were collected for molecular and pharmacokinetic studies. RESULTS: Sixteen patients were evaluable for dose-limiting toxicity (DLT). 240 mg was determined to be the RP2D wherein a single DLT occurred (1/7 patients). Treatment-related DLTs were not seen at lower doses. Best response was stable disease (SD) in 7 of 16 (44%) patients. HER2 amplification (chromogenic in situ IHC) was detected in 2 of 21 (9.5%) treatment-naïve tumors and 4 of 16 (25%) biopsies upon trial enrollment (post-anti-EGFR treatment and progression). Compared with matched enrollment biopsies, 6 of 8 (75%) blood samples showed concordance for HER2 CNV in circulating cell-free DNA. Five SD patients had HER2 amplification in either treatment-naïve or enrollment biopsies. Examination of gene-expression, total protein, and protein phosphorylation levels showed relative upregulation of ≥2 members of the HER-family receptors or ligands upon enrollment versus matched treatment-naïve samples. CONCLUSIONS: The RP2D of neratinib in this combination was 240 mg/day, which was well tolerated with low incidence of G3 AEs. There were no objective responses; SD was seen at all neratinib doses. HER2 amplification, detectable in both tissue and blood, was more frequent post-anti-EGFR therapy.

Validation of the NSABP/NRG Oncology 8-Gene Trastuzumab-benefit Signature in Alliance/NCCTG N9831.

Our objective was to validate the NSABP 8-gene trastuzumab-benefit signature, developed and initially validated in NRG Oncology/NSABP B-31 in Alliance/NCCTG N9831. The B-31 and N9831 trials demonstrated the benefit of adding trastuzumab to chemotherapy in the adjuvant setting for HER2+ breast cancer patients. NSABP investigators utilized gene expression profiles of N9831 patients (N = 892) to blindly assign patients to large-, moderate-, or no-trastuzumab benefit groups and then NCCTG investigators assessed the degree of trastuzumab benefit using Cox models adjusted for age, nodes, estrogen receptor/progesterone receptor status, tumor size, and grade. Hazard ratios and 2-sided P values for recurrence-free survival of the predicted large- (n = 387), moderate- (n = 401), and no-benefit (n = 104) groups, based on the 8-gene signature were 0.47 (95% CI = 0.31 to 0.73, P < .001), 0.60 (95% CI = 0.39 to 0.92, P = .02), and 1.54 (95% CI = 0.59 to 4.02, P = .38), respectively (P interaction  = .02), providing validation of the 8-gene signature in an independent study.

Correction to: NSABP FB-7: a phase II randomized neoadjuvant trial with paclitaxel + trastuzumab and/or neratinib followed by chemotherapy and postoperative trastuzumab in HER2+ breast cancer.

After the publication of this work [1] the authors have reported that in Table 3 The letter "T" in columns 5 and 7 should not be there.

NSABP FB-7: a phase II randomized neoadjuvant trial with paclitaxel + trastuzumab and/or neratinib followed by chemotherapy and postoperative trastuzumab in HER2+ breast cancer.

PURPOSE: The primary aim of NSABP FB-7 was to determine the pathologic complete response (pCR) rate in locally advanced HER2-positive (HER2+) breast cancer patients treated with neoadjuvant trastuzumab or neratinib or the combination and weekly paclitaxel followed by standard doxorubicin plus cyclophosphamide. The secondary aims include biomarker analyses. EXPERIMENTAL DESIGN: pCR was tested for association with treatment, gene expression, and a single nucleotide polymorphism (SNP) in the Fc fragment of the IgG receptor IIIa-158V/F (FCGR3A). Pre-treatment biopsies and residual tumors were also compared to identify molecular changes. RESULTS: The numerical pCR rate in the trastuzumab plus neratinib arm (50% [95%CI 34-66%]) was greater than that for single-targeted therapies with trastuzumab (38% [95%CI 24-54]) or neratinib (33% [95%CI 20-50]) in the overall cohort but was not statistically significant. Hormone receptor-negative (HR-) tumors had a higher pCR rate than HR+ tumors in all three treatment arms, with the highest pCR rate in the combination arm. Diarrhea was the most frequent adverse event and occurred in virtually all patients who received neratinib-based therapy. Grade 3 diarrhea was reported in 31% of patients; there were no grade 4 events. Our 8-gene signature, previously validated for trastuzumab benefit in two different clinical trials in the adjuvant setting, was correlated with pCR across all arms of NSABP FB-7. Specifically, patients predicted to receive no trastuzumab benefit had a significantly lower pCR rate than did patients predicted to receive the most benefit (P = 0.03). FCGR genotyping showed that patients who were homozygous for the Fc low-binding phenylalanine (F) allele for FCGR3A-158V/F were less likely to achieve pCR. CONCLUSIONS: Combining trastuzumab plus neratinib with paclitaxel increased the absolute pCR rate in the overall cohort and in HR- patients. The 8-gene signature, which is validated for predicting trastuzumab benefit in the adjuvant setting, was associated with pCR in the neoadjuvant setting, but remains to be validated as a predictive marker in a larger neoadjuvant clinical trial. HR status, and the FCGR3A-158V/F genotype, also warrant further investigation to identify HER2+ patients who may benefit from additional anti-HER2 therapies beyond trastuzumab. All of these markers will require further validation in the neoadjuvant setting. TRIALS REGISTRATION: ClinicalTrials.gov, NCT01008150. Retrospectively registered on October 5, 2010.

Incidence of Late Relapses in Patients With HER2-Positive Breast Cancer Receiving Adjuvant Trastuzumab: Combined Analysis of NCCTG N9831 (Alliance) and NRG Oncology/NSABP B-31.

PURPOSE: Recent trials have shown potential benefit of extended adjuvant endocrine therapy and relatively high risk of recurrence (RoR) after 5 years in hormone receptor-positive (HR+) human epidermal growth factor receptor 2-negative (HER2-) breast cancer. Although risk of late relapse in HR+ HER2- breast cancer is fairly well defined, the risk in HER2-positive (HER2+) breast cancer treated with adjuvant trastuzumab-based chemotherapy remains largely unknown. METHODS: We included 3,177 patients with HER2+ breast cancer treated with adjuvant chemotherapy alone or with trastuzumab from the North Central Cancer Treatment Group N9831 (ClinicalTrials.gov identifier: NCT00005970) and National Surgical Adjuvant Breast and Bowel Project B-31 (ClinicalTrials.gov identifier: NCT00004067) trials. RESULTS: Overall, HR+ breast cancer was significantly associated with improved recurrence-free survival (RFS) during the first 5 years (hazard ratio, 0.65; 95% CI, 0.56 to 0.77; P < .001). Among patients treated with trastuzumab, cumulative hazard for RFS was lower in patients with HR+ HER2+ breast cancer during the first 5 years (10.96% v 17.48%; hazard ratio, 0.60; 95% CI, 0.45 to 0.79; P < .001). However, there was no significant difference in RFS based on HR status during years 5 to 10 (hazard ratio, 1.32; 95% CI, 0.93 to 1.88; P = .12). A comparable degree of trastuzumab benefit was observed in HR+ and HR- breast cancers ( P for interaction = .87). Furthermore, we observed low RoR in years 5 to 10 among patients with HR+ HER2+ breast cancer: 3.23% in patients without lymph node involvement (N0) and 6.39% in patients with involvement of one to three lymph nodes (N1). CONCLUSION: The benefit of adjuvant trastuzumab persists for a long time. A distinct pattern of recurrence was observed between HR+ and HR- HER2+ disease but with similar degree of benefit from adjuvant trastuzumab. RoR in years 5 to 10 in HR+ HER2+ breast cancer is low, particularly in patients with N0 or N1 disease.

Stromal Tumor-infiltrating Lymphocytes in NRG Oncology/NSABP B-31 Adjuvant Trial for Early-Stage HER2-Positive Breast Cancer.

We retrospectively assessed association of stromal tumor-infiltrating lymphocytes (sTILs) with clinical outcomes and molecular variables reportedly predictive of trastuzumab-benefit in National Surgical Adjuvant Breast and Bowel Project B-31 (N = 2130). sTILs were assessed in 1581 eligible B-31 cases utilizing all available hematoxylin and eosin slides. Mean concordance between main reviewer and six other pathologists was 90.8% in 100 cases. Cox regressions were used to calculate hazard ratios (HRs). In chemotherapy and trastuzumab added to chemotherapy arms, increases in sTILs, as a semicontinuous variable (combined arms HR = 0.42, 95% confidence interval = 0.27 to 0.64, two-sided P < .001) or as lymphocyte-predominant breast cancer with more than 50% sTILs (combined arms HR = 0.65, 95% confidence interval = 0.49 to 0.86, two-sided P = .003) were statistically significantly associated with improved disease-free survival. There was no association of sTILs with trastuzumab benefit. However, higher sTILs were statistically significantly associated with higher trastuzumab benefit groups by 8-gene prediction model (two-sided P < .001). Neither PIK3CA mutations nor Fc-gamma-receptor polymorphisms were associated with sTILs. sTILs may have utility as a prognostic biomarker identifying HER2-positive early breast cancer at low recurrence risk.

Molecular subtypes of colorectal cancer in pre-clinical models show differential response to targeted therapies: Treatment implications beyond KRAS mutations.

Molecular subtypes of colorectal tumors are associated with prognosis and prediction for treatment benefit from chemotherapy. The purpose of this study was two-fold: 1) to determine the association of colorectal (CRC) molecular subtypes with response to targeted therapies in pre-clinical models and 2) to identify treatments for CRC stem-like subtype because these tumors are associated with a very poor patient prognosis. Eleven CRC cell lines were classified into molecular subtypes and tested for their response to pan-ERBB, MEK, and ERK inhibitors as single agents and in combination. All six inflammatory or TA cell lines were exquisitely sensitive to the combination of MEK and neratinib whereas all five stem-like cell lines were resistant. Growth inhibition in sensitive cell lines was greater with the combination than with either drug alone even in cell lines with KRAS mutations. The combination inhibited pERK in inflammatory cell lines but not in four out of five stem-like cell lines. MEK162 plus neratinib were synergistic in cell culture and xenograft models in inflammatory cell lines. The ERK inhibitor, SCH772984, down-regulated pERK, decreased cell viability, and was synergistic with neratinib in both inflammatory and stem-like subtypes. These results suggest that inhibition of pERK is a critical node in decreasing cell viability of stem-like CRC tumors. Our results also suggest that CRC molecular subtypes may yield predictive information and may help to identify patients who may respond to targeted inhibitors.

Tumour sidedness and intrinsic subtypes in patients with stage II/III colon cancer: analysis of NSABP C-07 (NRG Oncology).

BACKGROUND: We tested the association of colon tumour sidedness with prognosis and with molecular subtypes recently shown to be predictive of oxaliplatin benefit in stage III colon cancer. METHODS: NSABP/NRG C-07 trial (N=1603) was used to determine association of tumour sidedness with molecular subtypes and recurrence-free survival (RFS) and overall survival (OS). RESULTS: Sidedness was associated with molecular subtypes except stem-like/CMS4 subtype. Patients with stage III, left-sided tumours showed superior OS but not RFS. Sidedness was not associated with prediction of oxaliplatin benefit when combined with 5-Fu+LV. However, greater benefit from oxaliplatin was observed in a small subset of stage III patients with left-sided, enterocyte-subtype tumours (interaction HR=0.17, P=0.01). CONCLUSIONS: Sidedness was associated with molecular subtypes and was predictive of OS in stage III colon cancer but was not predictive of RFS or oxaliplatin benefit in C-07. Molecular subtypes may provide more predictive value for oxaliplatin benefit than tumour sidedness.

Association of Polymorphisms in FCGR2A and FCGR3A With Degree of Trastuzumab Benefit in the Adjuvant Treatment of ERBB2/HER2-Positive Breast Cancer: Analysis of the NSABP B-31 Trial.

IMPORTANCE: Preclinical models and studies in the metastatic and neoadjuvant settings suggest that single nucleotide polymorphisms in FCGR3A and FCGR2A may be associated with differential response to trastuzumab in the treatment of ERBB2/HER2-positive breast cancer, by modulating antibody-dependent cell-mediated cytotoxic effects. OBJECTIVE: To evaluate the effect of FCGR2A and FCGR3A polymorphisms on trastuzumab efficacy in the adjuvant treatment of ERBB2/HER2-positive breast cancer. DESIGN, SETTING, AND PARTICIPANTS: This is a retrospective analysis of patients enrolled in the National Surgical Adjuvant Breast and Bowel Project (NSABP) B-31 trial, a phase 3 cooperative group study conducted between 2000 and 2005. The NSABP B-31 trial randomized 2119 women with surgically resected node-positive, ERBB2/HER2-positive breast cancer to treatment with doxorubicin and cyclophosphamide followed by paclitaxel or the same regimen with the addition of 1 year of weekly trastuzumab. Patients were accrued at cooperative group sites across the United States and Canada. This analysis was performed between 2013 and 2016. INTERVENTIONS: Doxorubicin and cyclophosphamide followed by paclitaxel or the same regimen with the addition of 1 year of weekly trastuzumab. MAIN OUTCOMES AND MEASURES: Disease-free survival. RESULTS: The genotyped cohort (N = 1251) resembled the entire B-31 cohort based on clinical variables and the degree of benefit from trastuzumab. Median follow-up time was 8.2 years in the genotyped samples. The disease-free survival probability at 3, 5, and 8 years was 74% (95% CI, 71%-79%), 66% (95% CI, 62%-71%), and 58% (95% CI, 54%-63%) in patients who received ACT and 86% (95% CI, 83%-89%), 82% (95% CI, 79%-85%), and 78% (95% CI, 74%-81%) in patients who received ACTH. Addition of trastuzumab significantly improved patient outcome (hazard ratio [HR], 0.46; 95% CI, 0.37-0.57; P < .001). The expected trend for interaction between polymorphisms and trastuzumab was observed for both genes, but only FCGR3A-158 polymorphism reached statistical significance for interaction (P < .001). As hypothesized, patients with genotypes FCB3A-158V/V or FCB3A-158V/F received greater benefit from trastuzumab (HR, 0.31; 95% CI, 0.22-0.43; P < .001) than patients who were homozygous for the low-affinity allele (HR, 0.71; 95% CI, 0.51-1.01; P = .05). CONCLUSIONS AND RELEVANCE: The FCGR3A-158 polymorphism is predictive of trastuzumab efficacy in this cohort of patients with early ERBB2/HER2-positive breast cancer. Patients who are homozygous for phenylalanine at this position represent a considerable proportion of the population and, in contrast to previously reported analyses from similarly designed trials, our results indicate that trastuzumab may be less efficacious in these patients. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00004067.

Clinical Outcome From Oxaliplatin Treatment in Stage II/III Colon Cancer According to Intrinsic Subtypes: Secondary Analysis of NSABP C-07/NRG Oncology Randomized Clinical Trial.

IMPORTANCE: Oxaliplatin added to fluorouracil plus leucovorin therapy for patients with colon cancer has been shown to provide significant but modest absolute benefit for disease-free survival. However, acute and chronic neurotoxic effects from this regimen underscore the need for markers that predict oxaliplatin benefit. OBJECTIVE: To test our hypothesis that molecular subtypes of colon cancer would be associated with differential prognosis and benefit from oxaliplatin added to fluorouracil plus leucovorin therapy. DESIGN, SETTING, AND PARTICIPANTS: Participants in the NSABP C-07 trial were divided into discovery (n = 848) and validation (n = 881) cohorts based on the order of tissue block submission. A reestimated centroid using 72 genes was used to determine Colorectal Cancer Assigner subtypes and their association with oxaliplatin benefit in the discovery cohort. The validation cohort was examined with a locked-down algorithm for subtype classification and statistical analysis plan. Post hoc analysis included examination of the entire cohort with Colorectal Cancer Assigner, Colorectal Cancer Subtype (CCS), and Consensus Molecular Subtype (CMS) methods. INTERVENTIONS: Fluorouracil plus leucovorin with or without oxaliplatin. MAIN OUTCOMES AND MEASURES: Percent recurrence-free survival. RESULTS: Among 1729 patients, 744 (43%) were female and mean (SD) age was 58 (11) years. Although C-07 participants with stage III disease with an enterocyte subtype showed a statistically significant benefit from oxaliplatin in the discovery cohort (hazard ratio, 0.22 [95% CI, 0.09-0.56]; P = .001 [N = 65]), no statistically significant benefit was observed in the validation cohort (hazard ratio, 0.53 [95% CI, 0.22-1.24]; P = .14 [N = 70]). The stemlike subtype was associated with poor prognosis and lack of benefit from oxaliplatin treatment (HR, 0.99 [95% CI, 0.73-1.34]; P = .96 [N = 367]). Examination of the different subtyping methods shows that all 3 methods robustly identified patients with poor prognosis (stemlike, CCS-3, and CMS-4) in both stage II and III. CONCLUSIONS AND RELEVANCE: Patients with stemlike tumors may be appropriate for clinical trials testing experimental therapies because stemlike tumors were robustly identified and associated with a poor prognosis regardless of stage or chemotherapy regimen. The clinical utility of using subtyping for the identification of patients for treatment with oxaliplatin requires validation in independent clinical trial cohorts. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00004931.

Intrinsic subtypes, PIK3CA mutation, and the degree of benefit from adjuvant trastuzumab in the NSABP B-31 trial.

PURPOSE: Considerable molecular heterogeneity exists among human epidermal growth factor receptor 2 (HER2) -positive breast cancer regarding gene expression and mutation profiling. Evidence from preclinical, clinical neoadjuvant, and metastatic clinical trials suggested that PIK3CA mutational status and PAM50 intrinsic subtype of a tumor were markers of response to anti-HER2 therapies. We evaluated the predictive value of these two biomarkers in the adjuvant setting using archived tumor blocks from National Surgical Adjuvant Breast and Bowel Project (NSABP) trial B-31. PATIENTS AND METHODS: Expression data for 49 genes using the nCounter platform were used to generate PAM50 intrinsic subtypes for 1,578 archived tumor blocks from patients in the B-31 trial. Six PIK3CA hotspot mutations were examined by mass spectrometry of the primer extension products in a randomly selected subset (n = 671). We examined the heterogeneity of trastuzumab treatment effect across different subsets defined by each marker using Cox regression and disease-free survival as the end point. RESULTS: Seven hundred forty-one (47.0%) of 1,578 tumors were classified as HER2-enriched (HER2E) subtype, and 166 (24.7%) of 671 tumors had PIK3CA mutations. Hazard ratios (HRs) for trastuzumab in HER2E and other subtypes were 0.44 (95% CI, 0.34 to 0.58; P < .001) and 0.47 (95% CI, 0.35 to 0.62; P < .001), respectively (interaction P = .67). HRs for trastuzumab in PIK3CA wild-type and mutated tumors were 0.51 (95% CI, 0.37 to 0.71; P < .001) and 0.44 (95% CI, 0.24 to 0.82; P = .009), respectively (interaction P = .64). CONCLUSION: Unlike results seen in the metastatic and neoadjuvant clinical trials, PIK3CA and PAM50 intrinsic subtypes were not predictive biomarkers for adjuvant trastuzumab in NSABP B-31. These data suggest that results from the metastatic and neoadjuvant setting may not be always applicable to the adjuvant setting.

Predicting degree of benefit from adjuvant trastuzumab in NSABP trial B-31.

BACKGROUND: National Surgical Adjuvant Breast and Bowel Project (NSABP) trial B-31 suggested the efficacy of adjuvant trastuzumab, even in HER2-negative breast cancer. This finding prompted us to develop a predictive model for degree of benefit from trastuzumab using archived tumor blocks from B-31. METHODS: Case subjects with tumor blocks were randomly divided into discovery (n = 588) and confirmation cohorts (n = 991). A predictive model was built from the discovery cohort through gene expression profiling of 462 genes with nCounter assay. A predefined cut point for the predictive model was tested in the confirmation cohort. Gene-by-treatment interaction was tested with Cox models, and correlations between variables were assessed with Spearman correlation. Principal component analysis was performed on the final set of selected genes. All statistical tests were two-sided. RESULTS: Eight predictive genes associated with HER2 (ERBB2, c17orf37, GRB7) or ER (ESR1, NAT1, GATA3, CA12, IGF1R) were selected for model building. Three-dimensional subset treatment effect pattern plot using two principal components of these genes was used to identify a subset with no benefit from trastuzumab, characterized by intermediate-level ERBB2 and high-level ESR1 mRNA expression. In the confirmation set, the predefined cut points for this model classified patients into three subsets with differential benefit from trastuzumab with hazard ratios of 1.58 (95% confidence interval [CI] = 0.67 to 3.69; P = .29; n = 100), 0.60 (95% CI = 0.41 to 0.89; P = .01; n = 449), and 0.28 (95% CI = 0.20 to 0.41; P < .001; n = 442; P(interaction) between the model and trastuzumab < .001). CONCLUSIONS: We developed a gene expression-based predictive model for degree of benefit from trastuzumab and demonstrated that HER2-negative tumors belong to the moderate benefit group, thus providing justification for testing trastuzumab in HER2-negative patients (NSABP B-47).

Mutation profiling and microsatellite instability in stage II and III colon cancer: an assessment of their prognostic and oxaliplatin predictive value.

PURPOSE: The purpose of this study was to examine the prognostic and oxaliplatin predictive value of mismatch repair (MMR) status and common hot spot mutations, which we previously identified in stage II and III colon cancer. EXPERIMENTAL DESIGN: Mutations in BRAF, KRAS, NRAS, MET, and PIK3CA were profiled in 2,299 stage II and III colon tumors from National Surgical Adjuvant Breast and Bowel Project (NSABP) clinical trials C-07 (n = 1,836) and C-08 (n = 463) with Type Plex chemistry and mass spectrometry. C-07 tested the worth of adding oxaliplatin to 5-fluorouracil plus leucovorin, and C-08 tested the worth of adding bevacizumab to FOLFOX. Cox proportional hazard models were used to assess prognostic or oxaliplatin predictive value of mutations for tumor recurrence, overall survival (OS), and survival after recurrence (SAR). RESULTS: BRAF mutations were associated with MMR-deficient tumors (P < 0.0001), poor OS [HR, 1.46; 95% confidence interval (CI), 1.20-1.79; P ≤ 0.0002], and poor SAR (HR, 2.31; 95% CI, 1.83-2.95; P < 0.0001). Mutations in KRAS, NRAS, MET, and PIK3CA were not associated with recurrence, OS, or SAR. MMR-deficient tumors were associated with an improved prognosis based on recurrence (HR, 0.48; 95% CI, 0.33-0.70; P < 0.0001). Mutations and MMR status were not predictive for oxaliplatin benefit. CONCLUSIONS: This study shows that BRAF mutations profiled from stage II and III colon cancer tumors were associated with poor SAR and validates and explains, at least in part, previous observations associating it with poor OS. Profiling of all of these mutations is warranted for future clinical trials testing new targeted therapies that block relevant signaling pathways. Such clinical trials are under development at NSABP.

A rapid, sensitive, reproducible and cost-effective method for mutation profiling of colon cancer and metastatic lymph nodes.

BACKGROUND: An increasing number of studies show that genetic markers can aid in refining prognostic information and predicting the benefit from systemic therapy. Our goal was to develop a high throughput, cost-effective and simple methodology for the detection of clinically relevant hot spot mutations in colon cancer. METHODS: The Maldi-Tof mass spectrometry platform and OncoCarta panel from Sequenom were used to profile 239 colon cancers and 39 metastatic lymph nodes from NSABP clinical trial C-07 utilizing routinely processed FFPET (formalin-fixed paraffin-embedded tissue). RESULTS: Among the 238 common hot-spot cancer mutations in 19 genes interrogated by the OncoCarta panel, mutations were detected in 7 different genes at 26 different nucleotide positions in our colon cancer samples. Twenty-four assays that detected mutations in more than 1% of the samples were reconfigured into a new multiplexed panel, termed here as ColoCarta. Mutation profiling was repeated on 32 mutant samples using ColoCarta and the results were identical to results with OncoCarta, demonstrating that this methodology was reproducible. Further evidence demonstrating the validity of the data was the fact that the mutation frequencies of the most common colon cancer mutations were similar to the COSMIC (Catalog of Somatic Mutations in Cancer) database. The frequencies were 43.5% for KRAS, 20.1% for PIK3CA, and 12.1% for BRAF. In addition, infrequent mutations in NRAS, AKT1, ABL1, and MET were detected. Mutation profiling of metastatic lymph nodes and their corresponding primary tumors showed that they were 89.7% concordant. All mutations found in the lymph nodes were also found in the corresponding primary tumors, but in 4 cases a mutation was present in the primary tumor only. CONCLUSIONS: This study describes a high throughput technology that can be used to interrogate DNAs isolated from routinely processed FFPET and identifies the specific mutations that are common to colon cancer. The development of this technology and the ColoCarta panel may provide a mechanism for rapid screening of mutations in clinically relevant genes like KRAS, PIK3CA, and BRAF. TRIAL REGISTRATION: ClinicalTrials.gov: NSABP C-07: NCT00004931.