Multigene Testing Satus in 257 Lung Squamous Cell Carcinoma Cases: Clinical Profiling of BRAF V600E Mutation in Three Cases

Although multigene tests have provided the opportunity to have gene-targeted therapy in advanced non-small-cell lung cancers (NSCLC), multigene tests might not have been fully applied to patients with advanced or recurrent NSCLC featuring squamous cell carcinoma histology. The combined treatment of dabrafenib and trametinib has gained approval for advanced NSCLC cases harboring the BRAF V600E mutation. In a real-world setting, we assessed the biomarker testing status for 257 consecutive lung squamous cell carcinoma (LSCC) patients treated at a single educational university hospital from 2016 to 2023. The multigene test revealed that three cases had the BRAF V600E mutation without any other druggable gene alterations. We specifically compared three cases confirmed with a BRAF V600E mutation against other cases without the BRAF V600E mutation. All three cases were pathologically diagnosed as LSCC using specimens from mediastinal lymph nodes obtained by endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA). Two cases were never smokers, and one case was an ex-smoker. Interestingly, all three cases had a history of resected papillary thyroid carcinoma. Treatment with dabrafenib and trametinib resulted in favorable responses. The combination of dabrafenib and trametinib has shown effectiveness for patients with advanced rare cancers harboring the BRAF V600E mutation. Considering the potential for rare driver gene alterations, multigene testing should be a consideration in the management of LSCC.