AUTHOR=Wang Ye-Min , Cai Wei , Xue Qing-Ming , Zhang Jin-Yao , Zhou Lv , Xiong Su-Yi , Deng Huan 

TITLE=Prognostic role of different PD-L1 expression patterns and tumor-infiltrating lymphocytes in high-grade serous ovarian cancer: a systematic review and meta-analysis

JOURNAL=Frontiers in Immunology

VOLUME=14

YEAR=2023

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2023.1234894

DOI=10.3389/fimmu.2023.1234894

ISSN=1664-3224

ABSTRACT=<sec><title>Background</title><p>The prognostic value of programmed cell death ligand 1 (PD-L1) expression and tumor-infiltrating lymphocytes (TILs) in high-grade serous ovarian cancer (HGSOC) remains a controversial topic in the research field. To comprehensively assess the importance of PD-L1 and TILs in this particular subtype of ovarian cancer, we performed a meta-analysis.</p></sec><sec><title>Methods</title><p>We conducted a comprehensive search of PubMed, Embase, Scopus, Web of Science, and Cochrane Library databases up to December 25, 2022. The association between PD-L1, TILs, and survival outcomes was evaluated using the combined hazard ratios (HRs) and their corresponding 95% confidence intervals (CIs).</p></sec><sec><title>Results</title><p>This meta-analysis comprised 11 trials involving a total of 1746 cases. The results revealed no significant association between PD-L1 expression in tumor cells (TCs) and overall survival (OS, HR = 0.76, 95% CI: 0.52-1.09, <italic>p</italic> = 0.136) or progression-free survival (PFS, HR = 0.71, 95% CI: 0.4 -1.24, <italic>p</italic> = 0.230). Nevertheless, a correlation was observed between PD-L1 expression in immune cells (ICs) and OS (HR = 0.73, 95% CI: 0.55-0.97, <italic>p</italic> = 0.031). Furthermore, the presence of CD8<sup>+</sup> and PD-1<sup>+</sup> TILs was found to significantly enhance OS (HR = 0.70, 95% CI = 0.55-0.87, <italic>p</italic> = 0.002; HR = 0.57, 95% CI = 0.40-0.80, <italic>p</italic> = 0.001, respectively) and PFS (HR = 0.62, 95% CI = 0.41-0.92, <italic>p</italic> = 0.019; HR = 0.52, 95% CI = 0.35-0.78, <italic>p</italic> = 0.002, respectively), whereas the presence of CD3<sup>+</sup> and CD4<sup>+</sup> TILs was positively associated with OS (HR = 0.50, 95% CI = 0.29-0.87, <italic>p</italic> = 0.014; HR = 0.55, 95% CI = 0.34-0.91, <italic>p</italic> = 0.020, respectively).</p></sec><sec><title>Conclusion</title><p>This study indicates a positive correlation between ICs-derived PD-L1 and survival, while no significant correlation was observed between TCs-derived PD-L1 and prognosis. These results highlight the importance of studying PD-L1 expression in ICs as a prognostic predictor. In addition, the presence of TILs was found to significantly improve patient survival, suggesting that TILs may be a valuable prognostic biomarker.</p></sec><sec><title>Systematic review registration</title><p><uri xlink:href="https://www.crd.york.ac.uk/prospero/" xmlns:xlink="http://www.w3.org/1999/xlink">https://www.crd.york.ac.uk/prospero/</uri>, identifier CRD42022366411.</p></sec>