Uncommon V599E BRAF mutations in Japanese patients with lung cancer.

Recently, somatic mutations of the epidermal growth factor receptor (EGFR) gene and Braf gene were found in patients with lung cancer. These mutations might be correlated with a clinical response to molecular target therapy. Although a few Caucasian lung cancer patients harbored BRAF mutations, there have been no reports about the BRAF mutation in Japanese patients with lung cancer. We investigated BRAF mutations in Japanese lung cancer patients. The study included 129 surgically removed lung cancer cases from Nagoya City University Hospital. Braf, EGFR, and erbB2 mutations also were analyzed by reverse transcript polymerase chain reaction (RT-PCR) and direct sequencing. In exon 15, one BRAF mutation (1796 thymine to adenine; V599E) was found in nonsmoking woman with well-differentiated adenocarcinoma. We detected the 43 EGFR mutations, including 19 at exon 19 and 20 at exon 21 from the 129 patients analyzed (33.3%). We also detected one erbB2 mutation from 76 patients analyzed. All these mutations existed exclusively. V599E BRAF mutation was uncommon in Japanese lung cancer. All three genes mutations were predominantly found in female nonsmoking subjects with adenocarcinomas. However, completely exclusive mutation status would help us to choose custom-made molecular target therapy for the lung cancer.