Intake of Dietary Fruit, Vegetables, and Fiber and Risk of Colorectal Cancer According to Molecular Subtypes: A Pooled Analysis of 9 Studies
CANCER RESEARCH
Authors: Hidaka, Akihisa; Harrison, Tabitha A.; Cao, Yin; Sakoda, Lori C.; Barfield, Richard; Giannakis, Marios; Song, Mingyang; Phipps, Amanda, I; Figueiredo, Jane C.; Zaidi, Syed H.; Toland, Amanda E.; Amitay, Efrat L.; Berndt, Sonja, I; Borozan, Ivan; Chan, Andrew T.; Gallinger, Steven; Gunter, Marc J.; Guinter, Mark A.; Harlid, Sophia; Hampel, Heather; Jenkins, Mark A.; Lin, Yi; Moreno, Victor; Newcomb, Polly A.; Nishihara, Reiko; Ogino, Shuji; Obon-Santacana, Mireia; Parfrey, Patrick S.; Potter, John D.; Slattery, Martha L.; Steinfelder, Robert S.; Um, Caroline Y.; Wang, Xiaoliang; Woods, Michael O.; Van Guelpen, Bethany; Thibodeau, Stephen N.; Hoffmeister, Michael; Sun, Wei; Hsu, Li; Buchanan, Daniel D.; Campbell, Peter T.; Peters, Ulrike
Abstract
Protective associations of fruits, vegetables, and fiber intake with colorectal cancer risk have been shown in many, but not all epidemiologic studies. One possible reason for study heterogeneity is that dietary factors may have distinct effects by colorectal cancer molecular subtypes. Here, we investigate the association of fruit, vegetables, and fiber intake with four well-established colorectal cancer molecular subtypes separately and in combination. Nine observational studies including 9,592 cases with molecular subtypes for microsatellite instability (MSI), CpG island methylator phenotype (CIMP), and somatic mutations in BRAF and KRAS genes, and 7,869 controls were analyzed. Both case-only logistic regression analyses and polytomous logistic regression analyses (with one control set and multiple case groups) were used. Higher fruit intake was associated with a trend toward decreased risk of BRAF-mutated tumors [OR 4th vs. 1st quartile = 0.82 (95% confidence interval, 0.65-1.04)] but not BRAF-wildtype tumors [1.09 (0.97-1.22); P difference as shown in case-only analysis = 0.02]. This difference was observed in case-control studies and not in cohort studies. Compared with controls, higher fiber intake showed negative association with colorectal cancer risk for cases with microsatellite stable/MSI-low, CIMP-negative, BRAF-wildtype, and KRAS-wild-type tumors (Ptrend range from 0.03 to 3.4e-03), which is consistent with the traditional adenoma-colorectal cancer pathway. These negative associations were stronger compared with MSI-high, CIMP-positive, BRAF-mutated, or KRAS-mutated tumors, but the differences were not statistically significant. These inverse associations for fruit and fiber intake may explain, in part, inconsistent findings between fruit or fiber intake and colorectal cancer risk that have previously been reported. Significance: These analyses by colorectal cancer molecular subtypes potentially explain the inconsistent findings between dietary fruit or fiber intake and overall colorectal cancer risk that have previously been reported.
Molecular Landscape of BRAF-Mutant NSCLC Reveals an Association Between Clonality and Driver Mutations and Identifies Targetable Non-V600 Driver Mutations
JOURNAL OF THORACIC ONCOLOGY
Authors: Negrao, Marcelo, V; Raymond, Victoria M.; Lanman, Richard B.; Robichaux, Jacqulyne P.; He, Junqin; Nilsson, Monique B.; Ng, Patrick K. S.; Amador, Bianca E.; Roarty, Emily B.; Nagy, Rebecca J.; Banks, Kimberly C.; Zhu, Viola W.; Ng, Chun; Chae, Young Kwang; Clarke, Jeffrey M.; Crawford, Jeffrey A.; Meric-Bernstam, Funda; Ou, Sai-Hong Ignatius; Gandara, David R.; Heymach, John, V; Bivona, Trever G.; McCoach, Caroline E.
Abstract
Introduction: Approximately 4% of NSCLC harbor BRAF mutations, and approximately 50% of these are non-V600 mutations. Treatment of tumors harboring non-V600 mutations is challenging because of functional heterogeneity and lack of knowledge regarding their clinical significance and response to targeted agents. Methods: We conducted an integrative analysis of BRAF non-V600 mutations using genomic profiles of BRAF-mutant NSCLC from the Guardant360 database. BRAF mutations were categorized by clonality and class (1 and 2: RAS-independent; 3: RAS-dependent). Cell viability assays were performed in Ba/F3 models. Drug screens were performed in NSCLC cell lines. Results: A total of 305 unique BRAF mutations were identified. Missense mutations were most common (276, 90%), and 45% were variants of unknown significance. F468S and N581Y were identified as novel activating mutations. Class 1 to 3 mutations had higher clonality than mutations of unknown class (p < 0.01). Three patients were treated with MEK with or without BRAF inhibitors. Patients harboring G469V and D594G mutations did not respond, whereas a patient with the L597R mutation had a durable response. Trametinib with or without dabrafenib, LXH254, and lifirafenib had more potent inhibition of BRAF non-V600-mutant NSCLC cell lines than other MEK, BRAF, and ERK inhibitors, comparable with the inhibition of BRAF V600E cell line. Conclusions: In BRAF-mutant NSCLC, clonality is higher in known functional mutations and may allow identification of variants of unknown significance that are more likely to be oncogenic drivers. Our data indicate that certain non-V600 mutations are responsive to MEK and BRAF inhibitors. This integration of genomic profiling and drug sensitivity may guide the treatment for BRAF-mutant NSCLC. (C) 2020 International Association for the Study of Lung Cancer. Published by Elsevier Inc.