Introduction Ovarian carcinoma is associated with the highest mortality of all gynecologic malignancies. Even after optimal treatment, prognosis remains poor. There is no established biomarker to predict individual patient outcome.
Objective To evaluate the prognostic significance of PD-1 and PD-L1 expression in tumor tissues from patients with ovarian cancer.
Methods Tissue micro-arrays were prepared from routinely formalin-fixed, paraffin-embedded tumor tissues and examined immunohistochemically for the expression of programed cell death protein 1 (PD-1) and one of its ligands (PD-L1) on epithelial tumor cells, as well as on tumor- and stroma-infiltrating immune cells.
Results The presence of PD-1 positive tumor-infiltrating immune cells was significantly associated with prolonged overall survival. PD-1 and PD-L1 positive tumor-infiltrating immune cells were associated with the presence of lymph node metastases and higher tumor grade. Interestingly, the amount of PD-1/PD-L1 positive tumor- and stroma-infiltrating immune cells independent of PD-1 or PD-L1 expression did not show any significant correlation with prognostic variables.
Conclusion Our results highlight the prognostic value of PD-1 and PD-L1 positive tumor-infiltrating immune cells in ovarian carcinoma. Their association with favorable prognosis supports the hypothesis that the expression of PD-1 and PD-L1 on tumor-infiltrating immune cells represents a strong immune response.
- cystadenocarcinoma, serous
- ovarian cancer
- ovarian neoplasms
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DW and TH contributed equally.
Contributors PB: study design, data collection, data discussion, manuscript writing. FM, EM: statistical analysis, manuscript editing. KB: data collection, data discussion. PM: manuscript editing, data discussion. KWS, RK: manuscript editing. SK-B: study design, manuscript editing. AB: study design, histopathological evaluation, manuscript editing. DW, TH: study design, histopathological evaluation, data discussion, manuscript writing.
Funding The authors have not declared a specific grant for this research from any funding agency in the public, commercial or not-for-profit sectors.
Competing interests None declared.
Patient consent for publication Not required.
Ethics approval The study was approved by the ethics committee of the Medical Faculty of the University Duisburg-Essen (identifier: 16-6916-BO). Consent to participate was obtained from all patients.
Provenance and peer review Not commissioned; externally peer reviewed.
Data availability statement Data are available upon reasonable request.