Plasma levels of soluble programmed death ligand 1 (sPD-L1) in WHO II/III nasopharyngeal carcinoma (NPC): A preliminary study

Abstract

Plasma levels of soluble PD-L1 (sPD-L1) have been reported to be an independent prognostic factor in many malignant tumors. The expression of sPD-L1 in nasopharyngeal carcinoma (NPC) has not been reported. The purpose of this study was to evaluate the expression of sPD-L1 and analyze its correlation with clinical characteristics in patients with NPC.Thirty-five patients with stage I-IVa NPC were included. Plasma samples were obtained pretreatment. The sPD-L1 concentrations were measured by enzyme-linked immunosorbent assay (ELISA). The correlations of sPD-L1 expression with clinical parameters and laboratory data were analyzed.sPD-L1 was detected in 35 plasma samples, the mean sPD-L1 concentration was 45.47pg/ml. sPD-L1 was significantly higher in stage III-IVa (50.76±28.15pg/ml) compared to stage I-II (19.87±11.38pg/ml) (t=2.618, P=.013). sPD-L1 was also higher in stage N2-3 (52.03±28.98pg/ml) than that in N0-1 (32.88±23.75pg/ml) (t=2.096, P=.046). Univariate analysis identified that sPD-L1 level positively correlated with clinical stage (r=0.495, P=.002) and N stage (r=0.34, P=.046). Multivariate analysis showed the clinical stage was an independent factor affecting sPD-L1 expression.This is the first report to detect sPD-L1 in NPC. The study indicated sPD-L1 is quantifiable, convenient and easy to obtain. sPD-L1 may serve as a useful biomarker for evaluating tumor progression and therapeutic efficacy of NPC.