Immunohistochemical localization of programmed death-1 ligand-1 (PD-L1) in gastric carcinoma and its clinical significance.

The present study examined programmed death-1 ligand-1 (PD-L1) detected by immunohistochemical labeling in 102 cases of human gastric carcinoma, 10 adenoma and 10 normal tissues. The relationship between PD-L1 immunolocalization and clinical pathological features, as well as the prognosis of gastric carcinoma, was explored. There was no PD-L1 detectable in normal gastric tissues and very weak immunolabeling in gastric adenomas, but it could be detected in 42.2% of gastric carcinoma tissues. There was no correlation between PD-L1 immunolocalization and patient age, sex, tumor location or the degree of tumor differentiation in the gastric carcinomas. However, PD-L1 immunodetection was significantly correlated to tumor size, invasion, lymph node metastasis and survival time of patients. PD-L1 immunolabeling was significantly enhanced (P<0.01) when the tumor infiltrated into the deep muscular layers, with lymph node metastasis or survival time of less than 2 years, Moreover, multivariate analysis demonstrated that PD-L1 immunodetection could be used as an independent factor to evaluate the prognosis of gastric carcinoma.