RT Journal Article SR Electronic T1 Programmed Cell Death Ligand-1 (PDL-1) Correlates With Tumor Infiltration by Immune Cells and Represents a Promising Target for Immunotherapy in Endometrial Cancer JF Anticancer Research JO Anticancer Res FD International Institute of Anticancer Research SP 1367 OP 1376 DO 10.21873/anticanres.15606 VO 42 IS 3 A1 THOMAS HECKING A1 THORE THIESLER A1 JANINA HALBE A1 LUCIA OTTEN A1 FLORIAN RECKER A1 HEIDRUN GEVENSLEBEN A1 TIM MÜLLER A1 CYNTHIA SCHILLER A1 EVA K. EGGER A1 ROLF FIMMERS A1 MATTHIAS B. STOPE A1 GLEN KRISTIANSEN A1 ALEXANDER MUSTEA YR 2022 UL http://ar.iiarjournals.org/content/42/3/1367.abstract AB Background/Aim: Endometrial carcinoma (EC) is one of the most common gynecological cancers in the Western Hemisphere. Nevertheless, there are not enough appropriate treatment options, especially for advanced stages. The immune checkpoint blockade represents a promising alternative to established cancer therapies by suppressing the immune-inhibitory activity of the immune checkpoint factors programmed cell death-1 (PD-1) and programmed cell death ligand-1 (PD-L1). In the present study, we characterized the clinical relevance of the biomarker PD-L1 expression in terms of its prognostic capabilities in EC. Patients and Methods: Tumor tissue samples from 87 EC patients were retrospectively analyzed by immunohistochemistry (PD-L1, p16, estrogen receptor, progesterone receptor, HER2/neu, Ki-67, CD3, CD20, CD68). Results: A total of 17.3% of EC patients were PD-L1 positive. PD-L1 status did not represent a suitable prognostic marker in EC, but correlated with T3/T4stage, positive lymph node status, p16 expression, and absence of estrogen and progesterone receptor. PD-L1 positive tissues showed increased infiltration with lymphocytes, monocytes, and macrophages, although not statistically significant in every case. Conclusion: In EC, PD-L1 expression has no prognostic significance, but correlates with other oncogenic factors and indicates increased infiltration of the tumor with immune cells. Thus, PD-1/PD-L1 immunecheckpoint blockade seems to be very promising, at least in a subset of EC patients.