Correlation of PD-L1 Expression Tested by 22C3 and SP263 in Non-Small Cell Lung Cancer and Its Prognostic Effect on EGFR Mutation-Positive Lung Adenocarcinoma

Programmed death-ligand 1 (PD-L1) expression is tested by immunohistochemistry (IHC)-22C3, SP263, and SP142. The aim of this study is to evaluate the correlation among the three methods of PD-L1 IHC in non-small cell lung cancer (NSCLC) and clinical significance of PD-L1 expression in lung adenocarcinoma with an epidermal growth factor receptor (EGFR)-tyrosine kinase domain mutation. The results of 230 patients who were pathologically confirmed as having NSCLC; tested using PD-L1 IHC 22C3, SP263, and SP142 methods; and evaluated via the peptide nucleic acid clamping method to confirm EGFR mutation, were analyzed in this study. 164 patients underwent both the SP263 and 22C3 tests. There was a significant positive correlation between the outcomes of the two tests (Spearman correlation coefficient=0.912, p