First-line immune checkpoint therapy in metastatic squamous cell lung cancer harboring both EGFR mutation and high expression of PD-L1: A case report.

A 90-year-old female was admitted to our hospital with a history of a dry cough. Chest computed tomography (CT) scan showed a tumor shadow, and CT-guided lung biopsy revealed squamous cell carcinoma harboring an EGFR mutation. In addition, programmed death-ligand 1 (PD-L1) was highly expressed with a tumor proportion score (TPS) of >75%. Pembrolizumab therapy in the first-line setting was not effective, and the patient died at six months from the first visit. Squamous cell lung cancers (SCLCs) with both EGFR mutation and high expression of PD-L1 are very rare.