Background: Programmed cell death ligand 1 (PD-L1) expression with respect to genetic alternations has not been well established in non-small cell lung cancer (NSCLC), especially in the Asian population.
Methods: We reviewed 1370 NSCLC patients from a prospectively maintained database. Immunohistochemistry was performed on tumor cells and tumor-infiltrating lymphocytes (TILs) using the VENTANA (SP142) anti-PD-L1 antibody.