Do PD-1 and PD-L2 expressions have prognostic impact in hematologic malignancies?

Abstract

Background/aim: PD-1 (programmed death-1) is an immune checkpoint receptor that modulates T-cell activity in peripheral tissuesvia interaction with its ligands, PD-L1 (programmed death-ligand 1) and PD-L2 (programmed death-ligand 2). Tumor cells upregulatePD-L1 or PD-L2 to inhibit this T lymphocyte attack. Our goal was to determine the PD-1 and PD-L2 expression rates of varioushematologic malignancies, and evaluate whether PD-1 and PD-L2 expressions have an impact on prognosis.Materials and methods: For this purpose, pretreatment bone marrow biopsy specimens of 83 patients [42 multiple myeloma (MM),21 acute leukemia, and 20 chronic lymphocytic leukemia (CLL)] were stained with monoclonal antibody immunostains of PD-1 andPD-L2.Results: As a result, the overall expression rate of PD-1 was 26.2%, 4.8%, and 60% in patients with MM, acute leukemia, and CLL,respectively, whereas the PD-L2 expression rate was 61.9%, 14.3%, and 10% in patients with MM, acute leukemia, and CLL, respectively.Conclusion: Finally, we concluded that the role of the PD-1 pathway can be demonstrated by immunohistochemistry (IHC). Since weevaluated whether there is a correlation between the (IHC) results and survival of patients with MM, acute leukemia, and CLL, we couldnot demonstrate meaningful evidence that these markers have an impact on prognosis.