ABSTRACT
Programmed cell death-1 ( PD-1 ) is a member of the CD28/cytotoxic T lymphocyte-associated protein-4 (CTLA-4) family, expressed on activated T cells, B cells and macrophages.Programmed cell death-ligand 1 (PD-L1) can inhibit T cell proliferation , activation and cytokine secretion , and participate in the negative feedback regulation of T cell receptor signals.In a normal body, PD-1/PD-Ls signaling pathway plays an important role in maintaining immune tolerance,but can inhibit T cell immune response and promote tumor immune escape in case of tumor .The relationships between the expression and prognosis of PD-1/PD-L1 in soft tissue sarcoma ( STS ) and its biological significance , influencing factors of PD-1/PD-L1 expression , and research progress in related drugs and clinical applicability in STS are reviewed.