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

PURPOSE CDK4/6 inhibitors are used to treat estrogen receptor (ER)–positive metastatic breast cancer (BC) in combination with endocrine therapy. PALLET is a phase II randomized trial that evaluated the effects of combination palbociclib plus letrozole as neoadjuvant therapy. PATIENTS AND METHODS Postmenopausal women with ER-positive primary BC and tumors greater than or equal to 2.0 cm were randomly assigned 3:2:2:2 to letrozole (2.5 mg/d) for 14 weeks (A); letrozole for 2 weeks, then palbociclib plus letrozole to 14 weeks (B); palbociclib for 2 weeks, then palbociclib plus letrozole to 14 weeks (C); or palbociclib plus letrozole for 14 weeks. Palbociclib 125 mg/d was administered orally on a 21-days-on, 7-days-off schedule. Core-cut biopsies were taken at baseline and 2 and 14 weeks. Coprimary end points for letrozole versus palbociclib plus letrozole groups (A v B + C + D) were change in Ki-67 (protein encoded by the  MKI67 gene; immunohistochemistry) between baseline and 14 weeks and clinical response (ordinal and ultrasound) after 14 weeks. Complete cell-cycle arrest was defined as Ki-67 less than or equal to 2.7%. Apoptosis was characterized by cleaved poly (ADP-ribose) polymerase. RESULTS Three hundred seven patients were recruited. Clinical response was not significantly different between palbociclib plus letrozole and letrozole groups ( P = .20; complete response + partial response, 54.3% v 49.5%), and progressive disease was 3.2% versus 5.4%, respectively. Median log-fold change in Ki-67 was greater with palbociclib plus letrozole compared with letrozole (−4.1 v −2.2; P < .001) in the 190 evaluable patients (61.9%), corresponding to a geometric mean change of −97.4% versus −88.5%. More patients on palbociclib plus letrozole achieved complete cell-cycle arrest (90% v 59%; P < .001). Median log-fold change (suppression) of cleaved poly (ADP-ribose) polymerase was greater with palbociclib plus letrozole versus letrozole (−0.80 v −0.42; P < .001). More patients had grade 3 or greater toxicity on palbociclib plus letrozole (49.8% v 17.0%; P < .001) mainly because of asymptomatic neutropenia. CONCLUSION Adding palbociclib to letrozole significantly enhanced the suppression of malignant cell proliferation (Ki-67) in primary ER-positive BC, but did not increase the clinical response rate over 14 weeks, which was possibly related to a concurrent reduction in apoptosis.

BackgroundAn 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.MethodsThe 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).ResultsAmong 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.ConclusionsThis 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 RegistrationClinicalTrials.gov: NSABP C-07: NCT00004931

Stromal tumor-infiltrating lymphocytes (sTILs) are important prognostic and predictive biomarkers in triple-negative (TNBC) and HER2-positive breast cancer. Incorporating sTILs into clinical practice necessitates reproducible assessment. Previously developed standardized scoring guidelines have been widely embraced by the clinical and research communities. We evaluated sources of variability in sTIL assessment by pathologists in three previous sTIL ring studies. We identify common challenges and evaluate impact of discrepancies on outcome estimates in early TNBC using a newly-developed prognostic tool. Discordant sTIL assessment is driven by heterogeneity in lymphocyte distribution. Additional factors include: technical slide-related issues; scoring outside the tumor boundary; tumors with minimal assessable stroma; including lymphocytes associated with other structures; and including other inflammatory cells. Small variations in sTIL assessment modestly alter risk estimation in early TNBC but have the potential to affect treatment selection if cutpoints are employed. Scoring and averaging multiple areas, as well as use of reference images, improve consistency of sTIL evaluation. Moreover, to assist in avoiding the pitfalls identified in this analysis, we developed an educational resource available at www.tilsinbreastcancer.org/pitfalls.