ABSTRACT
@#[Abstract] Objective: Elevated levels of soluble PD-L1 (sPD-L1) are associated with worse prognosis of renal cell carcinoma and multiple myeloma. However, the regulatory roles and functions of sPD-L1 in advanced melanoma are not fully understood. This study was designed to evaluate the association between circulating sPD-L1 concentrations and prognosis of patients with advanced acral or mucosal melanoma. Methods: A total of 102 untreated patients with advanced acral and mucosal melanoma admitted to Peking University Cancer Hospital between January 2012 and December 2015 were enrolled in this study. In the meanwhile, peripheral blood samples were obtained from 40 healthy donors. Circulating sPD-L1 concentrations were determined using an enzyme-linked immunosorbent assay. Results: The advanced melanoma cohort included 58 acral melanoma patients and 44 mucosal melanoma patients. The pre-treatment concentration of sPD-L1 (2.91±2.23 ng/ml) in plasma of patients group was elevated as compared with that in healthy donors (0.59 ng/ml). The concentration of sPD-L1 in serum was significantly upregulated in 39/102 (38.2%) patients and significantly associated with increased LDH level (P=0.021) and number of Tregs (P=0.017). The overall survival rates of patients with high or low concentrations of sPD-L1 were statistically different (8.5 months [high level] vs 11.6 months [low level], P=0.022). Conclusion: sPD-L1 concentration is elevated in patients with advanced acral or mucosal melanoma, which may play an important role in predicting prognosis.