PurposeThe aim of this study was to evaluate prognostic importance of programmed death-1 (PD-1) and/ or programmed death-ligand 1 (PD-L1) expressions in type 2 endometrial cancer.Study designFormalin-fixed, paraffin-embedded tissue samples from 53 cases with type 2 endometrial cancer were analyzed. One-third of our cases had serous adenocarcinoma (32%), 11 had clear cell (21%) and 25 had mixed-type adenocarcinoma (47%). PD-1 and PD-L1 expressions in tumor tissue and microenvironment were detected by immunohistochemistry. Clinical and pathological characteristics including age, stage, initial symptom, surgical procedure, myometrial invasion, lymphovascular space invasion (LVSI), lymph node invasion, adjuvant therapy, and survival were reviewed. The Kaplan-Meier and Cox proportional hazards models were used to evaluate the prognostic factors.ResultsPD-1 expression in tumor tissue and microenvironment was detected in 22 (42%) and 28 (53%) cases, respectively. PD-L1 expression was detected in tumor and microenvironment in 8 (15%) and in 15 cases (28%), respectively. Expression of PD-1 and PD-L1 expressions in tumor area was associated with shorter survival (p=0.006 and 0.001, respectively) but PD-1 and PD-L1 expressions in microenvironment were not found to be related with survival. PD-1 (p=0.006) and PD-L1 expressions (p=0.001) in addition to LVSI (p=0.005), myometrial invasion (p=0.015), lymph node involvement (p=0.019), and suboptimal cytoreduction (p=0.042), were found to be associated with poor prognostic indicators. PD-1 and PD-L1 expressions in tumor and lymph node involvement were determined as independent prognostic factors.ConclusionPD-1 and PD-L1 expressions in type 2 endometrial cancers were found to be poor prognostic indicators.