ERCC1 and neoplasm: We also used immunohistochemical analysis to examine expression of five candidate protein biomarkers previously identified in the literature: vascular endothelial growth factor receptor 2 (VEGFR2) 9, 10, histone‐lysine‐N‐methyltransferase EZH2 (EZH2) 11, 12, DNA excision repair protein ERCC1 (ERCC1) 1, 13, DNA repair protein RAD51 homolog 1 (RAD51) 14, 15, and PKR16, 17 in resected tumor specimens from 98 NSCLC patients who were treated with neoadjuvant chemotherapy.