PD-1 and PD-L1 expression in 132 recurrent nasopharyngeal carcinoma: the correlation with anemia and outcomes

The expression of Programmed death-1 (PD-1) / programmed death-ligand 1 (PD-L1) has been reported to be reliable prognostic factors in various malignances including primary nasopharyngeal carcinoma (NPC). However, the exact role of PD-1/PD-L1 in recurrent NPC remains unclear. In this study, we aimed to investigate the relationship between the expression of PD-1 / PD-L1 and the clinical-pathology as well the outcomes of recurrent NPC patients (n = 132). The expression of PD-1 and PD-L1 was measured by immunohistochemistry staining. The relationship between PD-1 / PD-L1 and factors involved in clinic-pathology and outcomes of patients with NPC was assessed by correlation analysis. To further explore the association between PD-L1 and anemia, immunofluorescence analysis was performed to investigate the correlation of PD-L1 with hypoxia inducible factor-1 alpha (HIF-1 alpha). We observed that advanced rT classification and anemia status before salvage treatment was associated with high level of PD-L1 in recurrent NPC patients, and PD-L1 and was co-located with HIF-alpha in recurrent tumors by immunofluorescence analysis. Moreover, our result suggested that PD-L1 might be a negative indicator for recurrent NPC patients as well as age, rT classification, anemia and tumor necrosis at diagnose of recurrence. Taken together, our results revealed that PD-L1 might be a potential prognostic biomarker for recurrent NPC patients, and advanced re-stage, anemia might represent as candidate biomarkers for evaluating patients' response to anti-PD-1 / PD-L1-treatment. However, further studies are needed to clarify the underlying mechanism of hypoxia in immunosuppression process induced by PD-1 / PD-L1 axis.