PD-L1 Expression in Endometrial Serous Carcinoma and Its Prognostic Significance

Abstract

Purpose

Programmed death-ligand 1 (PD-L1) has been widely used as a prognostic biomarker and an immunotherapeutic target in numerous cancers, but information on the clinical significance of its expression in endometrial serous carcinoma (ESC) is largely lacking. Here, we evaluate the predictive value of PD-L1 expression in ESC.

Materials and Methods

A total of 79 cases of ESC accessioned between January 2003 and September 2015 were selected for further analysis. PD-L1 expression was evaluated in whole tissue sections of these cases by using the tumor proportion score (TPS, cut-off 1%) and combined positive score (CPS, cut-off 1) scoring methods.

Results

Overall, there was a heterogeneous expression of PD-L1, focal or patchy, in ESCs. PD-L1 positivity was observed in 43.0% of ESCs by TPS and 73.4% of ESCs by CPS. Kaplan–Meier survival analysis showed that patients with PD-L1-positive tumors suffered significantly worse OS and PFS, when compared with PD-L1 negative tumors (log-rank p = 0.037 and p = 0.003, respectively). In contrast, PD-L1 positivity by CPS within the ESC cases showed no statistical significance for OS and PFS (log-rank p = 0.720 and p = 0.928, respectively). Multivariate Cox analysis showed that PD-L1 positivity by TPS was significantly associated with PFS (HR = 1.921, p = 0.039) but not OS (HR = 1.229, p = 0.631).

Conclusion

PD-L1 expression is frequently found in ESC, suggesting a potential role of the PD-1/PD-L1 pathway as a potential therapeutic target for these tumors. PD-L1 expression by TPS also serves as a negative prognostic marker in ESC and implies an unfavorable outcome.

Keywords:

• PD-L1
• endometrial serous carcinoma
• endometrial cancer
• immune therapy

Acknowledgments

We are grateful to Junjie Zhu (Department of Epidemiology, School of Public Health, Fudan University, Shanghai, China/Department of Epidemiology and Health Statistics, School of Public Health, Dali University, Dali, China) for statistical technical assistance.

Abbreviations

ESC, endometrial serous carcinoma; PD-L1, programmed death-ligand 1; IHC, immunohistochemistry; BMI, body mass index; MI, myometrial invasion; LNM, lymph node metastasis; LVSI, lymphovascular space invasion; RD, residual disease; TPS, tumor proportion score; CPS, combined positive score; OS, overall survival; PFS, progression-free survival; HR, hazard ratio; CI, confidence interval.

Data Sharing Statement

The datasets generated or analyzed during the current study available from the corresponding author on reasonable request.

Ethics Approval and Consent to Participate

The study was approved by the Institutional Research Ethics Board at Zhejiang University School of Medicine Women’s Hospital, China (No: IRB-20200281-R). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the Helsinki declaration. Each enrolled patient permitted and signed up informed consent to use their samples and records for scientific research.

Author Contributions

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

Disclosure

The authors state they have no competing interests.