Expression of cancer cell-intrinsic PD-1 associates with PD-L1 and p-S6 and predicts a good prognosis in nasopharyngeal carcinoma

• Published in: Journal of Cancer Vol. 12; no. 20; pp. 6118 - 6125
• Main Authors: Zhang, Yuting, Chen, Xianyong, Zheng, Hongmei, Zhan, Yuting, Luo, Jiadi, Yang, Yang, Ning, Yue, Wang, Haihua, Wang, Weiyuan, Fan, Songqing
• Format: Journal Article
• Language: English
• Published: Wyoming Ivyspring International Publisher Pty Ltd 01.01.2021; Ivyspring International Publisher
• Subjects: Cancer therapies; Chemotherapy; Cytoplasm; Epstein-Barr virus; Ethics; Medical prognosis; Metastasis; Polyclonal antibodies; Proteins; Radiation therapy; Research Paper; Statistical analysis; Throat cancer; China
• ISSN: 1837-9664; 1837-9664
• DOI: 10.7150/jca.60739

Aims: Programmed cell death ligand 1 (PD-L1) is the ligand of programmed death 1 (PD-1), which is a host immunity inhibitory receptor. Expression of PD-L1 in diverse tumor types has been widely discussed, while there is little research about tumor intrinsic-PD-1. Phospho-S6 (p-S6) is an important downstream effector in the PI3K/AKT/mTOR pathway. Our study was focused on investigating expression of cancer cell-intrinsic PD-1, PD-L1 and p-S6 proteins and aimed to illustrate their relationship and clinical significances in nasopharyngeal carcinoma (NPC). Methods: The expression of PD-1, PD-L1 and p-S6 proteins in tissues of NPC, non-cancerous nasopharyngeal epithelia, primary cancer and matching metastatic lesion was detected by immunohistochemistry. Results: Expression of PD-1, PD-L1 and p-S6 proteins and co-expression of PD-1 and PD-L1 were significantly higher in NPC (all P< 0.05). The expression of PD-1 and co-expression of PD-1 and PD-L1 in paired metastatic NPC were significantly increased (all P< 0.01). NPC patients with positive expression of PD-L1 showed significantly higher overall survival rate (P =0.035). However, NPC patients with positive expression PD-1 and p-S6 showed significantly lower overall survival rate (P =0.031, P=0.044, respectively). Interestingly, NPC patients with co-expression of PD-1 and PD-L1 had lower overall survival rate (P=0.042). Multivariate Cox proportional hazard regression analysis confirmed that positive expression of PD-L1 and p-S6 were independent prognostic factors for NPC patients. Conclusions: Expression of cancer cell-intrinsic PD-1 associates with PD-L1 and p-S6 proteins, PD-L1 might serve as a good prognostic biomarker, while p-S6 could be an independent poor prognostic biomarker for NPC patients.