Expression of Programmed Death-1 Ligands (PD-L1 and PD-L2) in Endometrial Carcinoma: Immunohistochemical Study

Passant Essam Shibel1, Reem R Mamdouh2, Maha E Salama1

  • 1Department of Pathology, Faculty of Medicine, Cairo University, Egypt.

Abstract

Insights

Programmed Death Ligand-1 (PD-L1) and Programmed Death Ligand-2 (PD-L2) are expressed in endometrial carcinoma (EC). High expression of PD-L1 and PD-L2 in EC is linked to advanced tumor characteristics and suggests potential benefit from anti-PD-1 therapies.

Area of Science:

  • Oncology
  • Immunology
  • Pathology

Background:

  • Cancer immunotherapies leverage the relationship between immunity and cancer.
  • Immune checkpoint regulators, such as Programmed Death-1 (PD-1) and its ligands PD-L1 and PD-L2, are crucial targets.
  • PD-1 pathway antibodies show promise in treating various cancers, with some FDA-approved.

Purpose of the Study:

  • To investigate the immunohistochemical expression of PD-L1 and PD-L2 in tumor cells (TC) and immune cells (IC) within endometrial carcinoma (EC).
  • To correlate PD-L1 and PD-L2 expression with clinico-pathologic characteristics of EC.

Main Methods:

  • Examined PD-L1 and PD-L2 immunohistochemical expression in tumor cells (TC) and tumoral immune cells (IC).
  • Analyzed data from 62 endometrial carcinoma cases.

Main Results:

  • Positive tumor cell PD-L1 expression correlated with high tumor grade and stromal tumor-infiltrating lymphocytes (TILs).
  • High tumor cell PD-L2 expression was associated with non-endometrioid types, high tumor grade, and high FIGO stage.
  • Positive immune cell PD-L1 expression linked to non-endometrioid types, high tumor grade, high FIGO stage, and high stromal TILs; high immune cell PD-L2 expression correlated with lympho-vascular space invasion.
  • Direct correlation observed between PD-L1 and PD-L2 expression in both TC and IC; notable PD-L2 expression found in PD-L1 negative cases.

Conclusions:

  • PD-L1 and PD-L2 expression is present in EC, particularly in high-grade, high-stage, non-endometrioid, and TILs-rich tumors.
  • These findings highlight EC cases with specific characteristics as candidates for anti-PD-1 therapy.
  • Testing for both PD-L1 and PD-L2 may be beneficial for identifying patients who could gain from PD-1 pathway-targeting treatments.