Predictive Biomarkers and Personalized Medicine Characteristics of Lung Cancers Harboring NRAS Mutations

Purpose:We sought to determine the frequency and clinical characteristics of patients with lung cancer harboringNRASmutations. We used preclinical models to identify targeted therapies likely to be of benefit against NRAS-mutant lung cancer cells. Experimental Design:We reviewed clinical data from patients whose lung cancers were identified at six institutions or reported in the Catalogue of Somatic Mutations in Cancer (COSMIC) to harbor NRAS mutations. Six NRAS-mutant cell lines were screened for sensitivity against inhibitors of multiple kinases (i.e., EGFR, ALK, MET, IGF-1R, BRAF, PI3K, and MEK). Results:Among 4,562 patients with lung cancers tested,NRASmutations were present in 30 (0.7%; 95% confidence interval, 0.45%–0.94%); 28 of these had no other driver mutations. 83% had adenocarcinoma histology with no significant differences in gender. While 95% of patients were former or current smokers, smoking-related G:C>T:A transversions were significantly less frequent inNRAS-mutated lung tumors than KRAS-mutant non–small cell lung cancer [NSCLC; NRAS: 13% (4/30), KRAS: 66% (1772/2733), P < 0.00000001]. Five of 6 NRAS-mutant cell lines were sensitive to the MEK inhibitors, selumetinib and trametinib, but not to other inhibitors tested. Conclusion:NRASmutations define a distinct subset of lung cancers ( 1%) with potential sensitivity to MEK inhibitors. Although NRAS mutations are more common in current/former smokers, the types of mutations are not those classically associated with smoking. Clin Cancer Res; 19(9); 1–8. 2013 AACR.