Assessment of programmed cell death ligand-1 expression with multiple immunohistochemistry antibody clones in non-small cell lung cancer.

Abstract

Programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1) have been identified as novel targets for immunotherapy, with PD-L1 as a potential predictive biomarker. However, a specific antibody for PD-L1 expression is an immediate requirement. Meanwhile, the clinicopathological identification of patients with positive PD-L1 remains unclear. The present study adopted three anti-PD-L1 IHC antibodies, SP142, SP263, and UMAB228 to test PD-L1 expression in 84 non-small cell lung cancer (NSCLC) specimens. The concordance among antibodies was examined by analytical comparison, and the association between PD-L1 expression and clinicopathological factors was assessed. The samples from 41 (48.8%), 51 (60.7%), and 50 (59.5%) patients were detected as PD-L1 positive evaluated by antibody SP142, SP263, and UMAB228, respectively. The kappa coefficient was 0.53, 0.58, and 0.46 for SP263 vs. SP142, SP263 vs. UMAB228, and SP142 vs. UMAB228, respectively. On the other hand, the univariate analysis of consensus cases indicated that the PD-L1 expression was significantly correlated with tobacco use (χ2=4.25, P=0.04). The analytical comparison showed moderate concordance between SP142, SP263 and UMAB228, whereas SP263 exhibited higher overall positive rate. Moreover, PD-L1 positive rate was significantly higher in patients with smoking history, which might help in identifying patients who would benefit from PD-1/PD-L1 checkpoint inhibitors.