PD‐L1 expression by different scoring methods and different cutoff values and correlation with clinicopathological characteristics in gastric cancer: A retrospective study

Abstract We retrospectively enrolled 325 gastric cancer (GC) patients to investigate the associations of programmed death ligand‐1 (PD‐L1) expression with clinicopathological characteristics by different scoring methods and different cutoff values. PD‐L1 expression was evaluated by the tumor proportion score (TPS) and the combined positive score (CPS). The positive rate of PD‐L1 TPS ≥1%, CPS ≥1, CPS ≥5 and CPS ≥10 in our study were 12.0%, 87.4%, 69.8% and 42.2%, respectively. Multivariate analysis showed that PD‐L1 CPS ≥5 was related to high expression of Ki67 (OR = 2.658, 95% CI: 1.401–5.045, p = .003) and pTNM staging (p = .033). PD‐L1 CPS ≥10 was correlated with larger tumor size (OR = 2.322, 95% CI: 1.052–5.127, p = .037) and lymph node metastasis (OR = 2.495, 95% CI: 1.293–4.814, p = .006). It is expected that these results can provide a reference for screening GC patients with high PD‐L1 expression level.