Identification of a Novel BRAF Thr599dup Mutation in Lung Adenocarcinoma

BRAF mutations are known as oncogenic drivers of non-small cell lung cancer (NSCLC). BRAF inhibition has demonstrated anti-tumor activity in patients with BRAF V600E mutant NSCLC. Further molecular screening for novel BRAF thr599dup mutation is warranted. The novel BRAF Thr599dup gene mutation, for which the repeat amino acid-tyrosine is inserted between the 599th amino acid and the 600th amino acid in exon 15 of BRAF, was identified by next-generation sequencing (NGS) during routine clinical care in a lung carcinoma sample from an Asian never-smoker. Other putative driver alterations including EGFR, ALK were not found in that patient. BRAF Thr599dup gene mutation analysis was consistent with BRAF v600E gene mutation. Here we report a novel BRAF gene mutation with molecular characteristics consistent with those in BRAF-driven NSCLC. Our case expands the scope of BRAF gene mutations and provides broader molecular profiling for optimizing therapeutic options for patients with NSCLC. The new BRAF gene mutation has important clinical meaning for cancer patients.