Purpose: To investigate the prevalence, distribution, and prognostic role of BRAF mutations in a large cohort of white patients with non-small-cell lung cancer (NSCLC).
Patients and methods: A retrospective series of 1,046 NSCLCs-comprising 739 adenocarcinomas (ADCs) and 307 squamous cell carcinomas (SCCs)-was investigated for BRAF mutations. High-resolution melting analysis followed by sequencing and strip hybridization assay were used. All patients were also analyzed for KRAS and EGFR mutations.
Results: BRAF mutations were present in 36 ADCs (4.9%) and one SCC (0.3%; P = .001). Twenty-one of the mutations (56.8%) were V600E, and 16 (43.2%) were non-V600E. V600E mutations were significantly more prevalent in females (16 of 187 patients; 8.6%) than in males (five of 552 patients; 0.9%), as indicated by multivariate logistic regression analysis (hazard ratio [HR], 11.29; P < .001). V600E-mutated tumors showed an aggressive histotype characterized by micropapillary features in 80% of patients and were significantly associated with shorter disease-free and overall survival rates on both univariate (HR, 2.67; P < .001 and HR, 2.97; P < .001, respectively) and multivariate analyses (HR, 2.19; P = .011 and HR, 2.18; P = .014, respectively). All non-V600E mutations were found in smokers (P = .015) and were associated with neither clinicopathologic parameters nor prognosis. BRAF and EGFR were concomitantly mutated in two tumors.
Conclusion: We report for the first time to our knowledge that V600E and non-V600E BRAF mutations affect different patients with NSCLC. V600E mutations are significantly associated with female sex and represent a negative prognostic factor. In addition, we identified a number of other clinicopathologic parameters potentially useful for the selection of patients carrying BRAF mutations.