The cell surface receptor programmed death-1 (PD1) and its ligand (PDL1) have been detected in various cancer types. It has been reported that expression of PDL1 and PD1 in a tumor is associated with poor prognosis of the patient. In the present study, we retrospectively examined tumor expression of PDL1 and intratumoral PD1(+) cell infiltration, and assessed their relationship with patient prognosis according to the pathological stage of gastric cancer.

PDL1 and PD1 expression in primary tumors from 431 patients was evaluated using immunohistochemistry. The association between the expression of PDL1/PD1 and clinicopathological features was assessed.

High expression of PDL1 was observed in 128 (29.6%) patients. PDL1 expression was correlated with tumor infiltration of PD1(+) cells. In multivariate analysis, PDL1 expression was associated with worse overall survival. In subset analysis, PDL1 expression was significantly associated with survival in patients with stage II/III gastric cancer. In conclusion, PDL1 was an independent prognostic factor for patients with stage II/III gastric cancer. Our results suggested that patients with stage II/III gastric cancer might be appropriate for PD1/PDL1-targeted therapy.