PD-L1 Expression in High-Grade Serous and Clear Cell Ovarian Cancer

Abstract

Purpose: Programmed death-ligand 1 (PD-L1) was expressed in various gynecology tumors. High-grade ovarian cancers could be a potential target for immune anti-PD-L1 modulate therapy. Antibodies targeting PD-L1 molecules are emerging cancer therapeutics. This study was designed to evaluate the expression of PD-L1 marker in the high-grade ovarian cancer types and evaluate its prognostic potential. Methods: The study included 18 patients with ovarian high-grade serous cancer (HGSC) and 11 patients with clear cell cancer (CCC) histology type, both in the International Federation of Gynecology and Obstetrics (FIGO) stage I. The expression of the PD-L1 marker was measured by tissue microarray-based immunohistochemistry. Expression levels of PD-L1 were correlated with the presence of tumor-infiltrating lymphocyte (TIL) and other histopathology parameters. Results: HGSC ovarian cancers predominantly had low PD-L1 expression, while CCC ovarian cancers had high PD-L1 expression (p < 0.001). PD-L1 expression did not show significant differences considering analyzed parameters other than histology type (localization, size, FIGO stage, lymphovascular invasion, tumor necrosis, and presence of TIL) among all ovarian cancers. There was no statistically significant difference in any of the tumor characteristics within histologic types of ovarian cancers. Conclusion: PD-L1 expression was significantly higher in clear cell histology type than in high-grade serous ovarian cancers in FIGO I stage. © 2022, The Author(s) under exclusive licence to Association of Gynecologic Oncologists of India.