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

The results of the 22C3 and those of SP263 methods were in good correlation with one another. Since the PD-L1 expression is not influenced by the EGFR mutation, it is necessary to perform a PD-L1 test to set the treatment direction in the patients with EGFR-mutant NSCLC.

The

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<0.001), with a derived regression equation as follows: 22C3=15.2+0.884×SP263 (R²=0.792, p<0.001). There was no relationship between the expression of PD-L1 and clinical parameters, including EGFR-tyrosine kinase inhibitor (TKI) mutation. The PD-L1 expression in patients treated with EGFR-TKI yielded a 2-month-shorter progression period than that in the PD-L1-negative group. However, this did not reach statistical significance (PD-L1<1% vs. PD-L1≥1%, 10 months vs. 8 months).