The clinicopathological and prognostic significance of PD-1 expression in cancers: A bioinformatics analysis

Background: Programmed cell death protein 1 (PD-1), which is encoded by PDCD1 gene, is a cell-surface protein of immunoglobin family. A number of published studies have reported the relationship between PD-1 expression and prognosis in cancers. The purpose of our study was to identify an independent prognostic marker. Methods: In the present study, we investigated the prognostic value of PD-1 mRNA expression through the Kaplan–Meier plotter databases. Results: The expression of PD-1 mRNA was negatively related with the overall survival (OS) rate of gastric cancer, but positively associated with the OS rate of breast cancer, ovarian cancer and liver cancer (P < 0.05). High PD-1 mRNA expression was linked to an improved relapse-free survival rate of breast cancer, ovarian cancer, and liver cancer (P < 0.05). There was a negative correlation with post-progression survival in gastric cancer (P < 0.05). Besides, there was a positive correlation with progression-free survival and disease specific survival in liver cancer. We also further evaluated the prognostic value of PD-1 in relation to different clinicopathological features of cancers. Conclusion: Our results showed that PD-1 expression might be a good marker for the prognosis of patients with cancers, which highlights new methods and ideas for preventive treatment.