The expression and clinical significance of programmed cell death receptor 1 and its ligand in tumor tissues of patients with extranodal nasal NK/T cell lymphoma

Appropriate biomarkers may help distinguish the biological behavior of different types of lymphoma and their response to traditional chemotherapy. Extranodal natural killer/T-cell lymphoma (ENKTL) and diffuse large B-cell lymphoma (DLBCL) belong to different subtypes of non-Hodgkin's lymphoma, the biological behavior and prognosis of them are very different, programmed cell death receptor 1 (PD-1) and its ligand (PD-L1) have been investigated in these two types of diseases. However, few studies addressed the difference of PD-1/PD-L1 levels between ENKTL and DLBCL, in order to find out the difference and related clinical application value, the clinical data and tumor tissue paraffin sections of 24 newly diagnosed ENKTL patients and 42 newly diagnosed diffuse large B-cell lymphoma (DLBCL) were collected. PD-1/PD-L1 levels in tumor tissues were detected by immunohistochemical staining. The relationship between the PD-1/PD-L1 levels and clinical data of patients with ENKTL patients was analyzed. Both patient groups showed PD-1 level in tumor tissue of ENKTL patients was significantly lower than that of DLBCL patients (P < 0.05), while the PD-L1 level in tumor tissues of ENKTL patients was not different from DLBCL (P < 0.05). In addition, the ENKTL patients with B symptoms, elevated lactate dehydrogenase (LDH) levels and decreased hemoglobin (HGB) concentrations had lower level of PD-1 in tumor tissue. PD-L1 level in tumor tissues, the LDH level, Epstein-Barr genome (EBV-DNA) copy and Ki-67 index may affect the outcomes of ENKTL patients (P < 0.05), but they were not independent factors. PD-L1 levels in tumor tissues has clinical significance in ENKTL patients, which suggested that the PD-1/PD-L1 signal pathway may be involved in the immune escape of ENKTL and play different roles in different lymphoma subtypes.