PD-1 and PD-L1 in locoregionally advanced nasopharyngeal carcinoma: Substudy of a randomized phase III trial

Background To evaluate the expression of programmed death-1 (PD-1) and programmed death-ligand 1 (PD-L1) by using immunohistochemistry analysis in locoregionally advanced nasopharyngeal carcinoma (NPC) patients receiving cisplatin, fluorouracil, and docetaxel followed by concurrent chemoradiotherapy. Methods As part of a previously reported trial, 108 patients were enrolled in this study. Results We observed that Epstein-Barr Virus (EBV) antibody levels were associated with PD-1 positive staining in NPC and PD-1 positive staining was identified as an independent prognostic factor for progression-free survival (hazard ratio 0.363, 95% confidence interval 0.134-0.987, P = .047). By contrast, the correlation between the PD-L1 level and hemoglobin, lactate dehydrogenase and high-sensitivity C-reactive protein was not identified. Moreover, high levels of PD-L1 staining were not significantly associated with clinical outcomes. Conclusion NPC patients with negative PD-1 staining had a significantly reduced survival outcome. Furthermore, patients with positive PD-1 staining had significantly higher EBV antibody levels.