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Casey B Williams,1,* Caitlin McMahon,2,* Siraj M Ali,2 Mark Abramovitz,1 Kirstin A Williams,1 Jessica Klein,1 Heidi McKean,1 Roman Yelensky,2 Thomas J George Jr,3 Julia A Elvin,2 Salil Soman,4 Doron Lipson,2 Juliann Chmielecki,2 Deborah Morosini,2 Vincent A Miller,2 Philip J Stephens,2 Jeffrey S Ross,2,5 Brian Leyland-Jones1 1Avera Cancer Institute, Sioux Falls, SD, USA; 2Foundation Medicine, Inc., Cambridge, MA, USA; 3University of Florida College of Medicine, Gainesville, FL, USA; 4Beth Israel Deaconess Medical Center, Boston, MA, USA; 5Albany Medical College, Albany, NY, USA *These authors contributed equally to this work Abstract: The subset of metastatic colorectal adenocarcinomas that harbor BRAF V600E mutations are aggressive tumors with significantly shortened survival and limited treatment options. Here we present a colorectal cancer patient whose disease progressed through standard chemotherapy and who developed liver metastasis. Comprehensive genomic profiling (FoundationOne®) identified a BRAF V600E mutation in the liver lesion, as well as other genomic alterations consistent with colorectal cancers. Combination therapy of dabrafenib and trametinib with standard cytotoxic chemotherapy resulted in a durable major ongoing response for the patient. This report illustrates the utility of comprehensive genomic profiling with personalized targeted therapy for aggressive metastatic colorectal adenocarcinomas. Keywords: oxaliplatin, colorectal adenocarcinoma, combination targeted therapy, BRAF mutations

Purpose: To assess the prognostic and predictive value of selected biomarkers involved in cell-cycle regulation or proliferation in patients with HER2-positive early breast cancer. Experimental Design: Protein expression of TOP2A, Ki67, cyclin D1, and p27 was immunohistochemically determined in tissue microarrays of surgical specimens from 862 patients randomized to trastuzumab (1 or 2 years; N ¼ 561) and observation (N ¼ 301) arms of the HERA trial. The primary analysis endpoint was disease-free survival (DFS). Biomarkers were examined as continuous or categorical variables (predefined cutoffs). Interaction terms between biomarkers and treatment were assessed in multivariate Cox models adjusted for variables of clinical interest. Results: A significant interaction was detected between p27 and treatment (adjusted P ¼ 0.0049). Trastuzumab effect was significant in the p27-low subgroup (70% p27-positive tumor cells; N ¼ 318). HRComb Trast vs.Obs 0.44, 95% CI, 0.29–0.65 (P < 0.001). No trastuzumab effect was observed in the p27-high subgroup N ¼ 435; HRComb Trast vs.Obs 0.97, 95% CI, 0.66–1.44, P ¼ 0.89), indicating that these patients derived little or no benefit from trastuzumab treatment. A prognostic effect of p27 on DFS was observed, with p27-high patients experiencing half the hazard of a DFS event compared with low ones (HRp27 High vs.Low 0.49, 95% CI, 0.32–0.75). TOP2A, Ki67, and cyclin D1, as categorical variables were not predictive, whereas cyclin D1 as continuous variable was predictive of trastuzumab benefit. Conclusions: In TransHERA, patients with HER2-positive early breast cancer with low p27 expression in their tumors benefited from trastuzumab treatment, whereas patients with high p27 expression did not. © 2018 American Association for Cancer Research.

Purpose The Herceptin Adjuvant study is an international multicenter randomized trial that compared 1 or 2 years of trastuzumab given every 3 weeks with observation in women with human epidermal growth factor 2-positive (HER2+) breast cancer after chemotherapy. Identification of biomarkers predictive of a benefit from trastuzumab will minimize overtreatment and lower health care costs. Methods To identify possible single-gene biomarkers, an exploratory analysis of 3,669 gene probes not expected to be expressed in normal breast tissue was conducted. Disease-free survival (DFS) was used as the end point in a Cox regression model, with the interaction term between C8A mRNA and treatment as a categorical variable split on the cohort mean. Results A significant interaction between C8A mRNA and treatment was detected (P < .001), indicating a predictive response to trastuzumab treatment. For the C8A-low subgroup (mRNA expression lower than the cohort mean), no significant treatment benefit was observed (P = .73). In the C8A-high subgroup, patients receiving trastuzumab experienced a lower hazard of a DFS event by approximately 75% compared with those in the observation arm (hazard ratio [HR], 0.25; P < .001). A significant prognostic effect of C8A mRNA also was seen (P < .001) in the observation arm, where the C8A-high group hazard of a DFS event was three times the respective hazard of the C8A-low group (HR, 3.27; P < .001). C8A mRNA is highly prognostic in the Hungarian Academy of Science HER2+ gastric cancer cohort (HR, 1.72; P < .001). Conclusion C8A as a single-gene biomarker prognostic of DFS and predictive of a benefit from trastuzumab has the potential to improve the standard of care in HER2+ breast cancer if validated by additional studies. Understanding the advantage of overexpression of C8A related to the innate immune response can give insight into the mechanisms that drive cancer. © 2019 American Society of Clinical Oncology.

IMPORTANCE A number of studies suggest that response to antihuman epidermal growth factor receptor-2 (currently known as ERBB2, but referred to as HER2 in this study) agents differs by estrogen receptor (ER) level status. The clinical relevance of this is unknown. OBJECTIVE To determine the magnitude of trastuzumab benefit according to quantitative levels of ER and HER2 in the HERceptin Adjuvant (HERA) trial. DESIGN, SETTING, AND PARTICIPANTS The HERA trialwas an international, multicenter, randomized trial that included 5099 patients with early-stage HER2-positive breast cancer, randomized between 2001 and 2005 to receive either no trastuzumab or trastuzumab, after adjuvant chemotherapy. This is a secondary analysis of the HERA study. Local ER immunohistochemical (IHC) analyses, HER2 fluorescence in situ hybridization (FISH) ratio, and copy number results were available for 3037 patients (59.6%) randomized to observation and trastuzumab (1 or 2 years) (cohort 1). Transcript levels of ESR1 and HER2 genes were available for 615 patients (12.1%) (cohort 2). INTERVENTIONS Patients were randomized to receive either no trastuzumab or 1 year vs 2 years of trastuzumab. Endocrine therapy was given to patients with hormone receptor-positive disease as per local guidelines. MAIN OUTCOMES AND MEASURES Disease-free survival (DFS) and overall survival (OS)were the primary and secondary end points in the intent-To-Treat population (ITT). Analyses adjusting for crossover (censored and inverse probability weighted [IPW]) were also performed. Interactions among treatment, ER status, and HER2 amplification using predefined cutoffs were assessed in Cox proportional hazards regression models. RESULTS Median follow-up time was 8 years. Levels of FISH and HER2 copy numbers were significantly higher in ER-negative patients (P < .001). In cohort 1, for DFS and OS, a significant treatment effect was found for all ER, IHC, and FISH levels, except for the ER-positive/HER2 low FISH ratio (≥2 to