High serum levels of soluble PD‑1 and PD‑L1 are associated with advanced clinical stages in patients with cervical cancer.

The binding of programmed cell death receptor-ligand 1 (PD-L1) to programmed cell death protein 1 (PD-1) inhibits T-cell activation, playing a negative role in the anticancer immune response. The soluble forms of these proteins, found in blood circulation, have recently received increasing attention and their function in the cancer immune response remains unclear. The present study evaluated the serum levels of soluble (s)PD-1 and sPD-L1 in patients with cervical cancer and healthy controls, and their associations with clinicopathological characteristics and clinical outcomes. The serum concentrations of both soluble proteins were determined via ELISA. The concentrations of sPD-1 and sPD-L1 were higher in patients with cervical cancer and advanced clinical stages. The evaluation of sPD-1 and clinical outcome revealed higher levels in deceased patients than in total remission patients. sPD-1 and sPD-L1 concentrations were moderately positively correlated; however, in patients with clinical stage IV disease, a very strong correlation was observed. sPD-1 and sPD-L1 could be used as potential diagnostic biomarkers for patients with cervical cancer. Considering the higher levels in advanced clinical stages, their role in cervical cancer progression or treatment response must be explored.