Background/aim: The expression of tumor-associated programmed death-ligand 1 (PD-L1) predicts clinical responses to PD-1-directed immunotherapy. The expression levels of PD-L2, another PD-1 ligand, and its relationship with responses to PD-1-targeting therapy in oral squamous cell carcinoma (OSCC) remain unclear. Furthermore, the clinicopathological characteristics and prognostic effects of the expression of PD-L1 and PD-L2 in OSCC have not yet been elucidated.
Materials and methods: The expression of PD-L1 and PD-L2 was immunohistochemically examined in 98 tongue carcinomas. Furthermore, the expression levels of PD-L1 and PD-L2 in OSCC cell lines and their relationships with those of MMP2 and MMP9 were assessed.
Results: The expression levels of PD-L1 and PD-L2 correlated with those of MMP2 and MMP9. The expression of PD-L1 and/or PD-L2 was detected in OSCC cells, and their levels correlated with those of MMP9. The prognosis of patients with PD-L1- and PD-L2-positive tumors was significantly worse.
Conclusion: PD-L1 and PD-L2 status is potentially a novel predictor of the prognosis of OSCC and provides a rationale for the development of novel immunotherapies.
Keywords: PD-L1; PD-L2; Tongue cancer; prognosis.
Copyright© 2021, International Institute of Anticancer Research (Dr. George J. Delinasios), All rights reserved.