Discordance of PD-L1 expression in primary and metastatic ovarian high-grade serous carcinoma and its correlation with CD8 + tumor-infiltrating lymphocytes and patient prognosis

The emerging and challenging role of PD-L1 in patients with gynecological cancers: An updating review with clinico-pathological considerations

Over recent years, there has been significant progress in the development of immunotherapeutic molecules designed to block the PD-1/PD-L1 axis. These molecules have demonstrated their ability to enhance the immune response by prompting T cells to identify and suppress neoplastic cells. PD-L1 is a type 1 transmembrane protein ligand expressed on T lymphocytes, B lymphocytes, and antigen-presenting cells and is considered a key inhibitory checkpoint involved in cancer immune regulation. PD-L1 immunohistochemical expression in gynecological malignancies is extremely variable based on tumor stage and molecular subtypes. As a result, a class of monoclonal antibodies targeting the PD-1 receptor and PD-L1, known as immune checkpoint inhibitors, has found successful application in clinical settings. In clinical practice, the standard method for identifying suitable candidates for immune checkpoint inhibitor therapy involves immunohistochemical assessment of PD-L1 expression in neoplastic tissues. The most commonly used PD-L1 assays in clinical trials are SP142, 28-8, 22C3, and SP263, each of which has been rigorously validated on specific platforms. Gynecologic cancers encompass a wide spectrum of malignancies originating from the ovaries, uterus, cervix, and vulva. These neoplasms have shown variable response to immunotherapy which appears to be influenced by genetic and protein expression profiles, including factors such as mismatch repair status, tumor mutational burden, and checkpoint ligand expression. In the present paper, an extensive review of PD-L1 expression in various gynecologic cancer types is discussed, providing a guide for their pathological assessment and reporting.

Expression of B7-H3 and TIM-3 in gastric-type endocervical adenocarcinoma: prevalence, association with PD-L1 expression, and prognostic significance

Gastric-type endocervical adenocarcinoma (GEA) is the second most common subtype of endocervical adenocarcinoma and has a poor prognosis. Anti-programmed death-1 and anti-programmed death-ligand 1 (PD-L1) inhibitors have emerged as a major treatment option for GEA; however, data on the expression of other immune checkpoints in GEA are limited. We analyzed the expression of T-cell immunoglobulin and mucin-domain containing-3 (TIM-3) and B7 homolog 3 protein (B7-H3) in 58 GEA and investigated their prognostic significance as well as association with PD-L1 expression and other known prognostic factors. Applying the tumor proportion score (TPS) with a cutoff of 1%, B7-H3 and TIM-3 were present in 48.3% and 17.2% of cases, respectively. Applying the combined positive score (CPS) with a cutoff of 1, TIM-3 expression was present in 70.7% of cases. Moreover, the expression of three checkpoints (B7-H3, TIM-3, and PD-L1) was incompletely overlapping. Patients with B7-H3 positive tumors (by TPS) or TIM-3 positive tumors (by TPS) had significantly worse recurrence-free survival (RFS) and overall survival (OS) (log-rank). Using CPS, patients with TIM-3 positive tumors showed significantly worse RFS (log-rank). Similarly, B7-H3 positivity (by TPS) and TIM-3 positivity (by TPS) were associated with worse RFS and OS in univariate analysis. TIM-3 positivity (by CPS) was associated with worse RFS in univariate analysis and the final Cox multivariate analysis. In conclusion, our results show that (1) B7-H3 and TIM-3 are frequently expressed in GEA and their expression overlaps incompletely with PD-L1; and (2) both B7-H3 and TIM-3 are independent negative prognostic markers in GEA.

Prognostic Significance of Programmed Cell Death Ligand 1 Expression in High-Grade Serous Ovarian Carcinoma: A Systematic Review and Meta-Analysis

(1) Background: High-grade serous ovarian carcinoma (HGSOC) is an aggressive subtype of ovarian cancer. Recent advances have introduced prognostic markers and targeted therapies. Programmed cell death ligand 1 (PD-L1) has emerged as a potential biomarker for HGSOC, with implications for prognosis and targeted therapy eligibility; (2) Methods: A literature search was conducted on major databases, and extracted data were categorized and pooled. Subgroup analysis was performed for studies with high heterogeneity. (3) Results: Data from 18 eligible studies were categorized and pooled based on PD-L1 scoring methods, survival analysis types, and endpoints. The result showed an association between high PD-L1 expression and a favorable prognosis in progression-free survival (HR = 0.53, 95% CI = 0.35-0.78, p = 0.0015). Subgroup analyses showed similar associations in subgroups of neoadjuvant chemotherapy patients (HR = 0.6, 95% CI = 0.4-0.88, p = 0.009) and European studies (HR = 0.59, 95% CI = 0.42-0.82, p = 0.0017). In addition, subgroup analyses using data from studies using FDA-approved PD-L1 antibodies suggested a significant association between favorable prognosis and high PD-L1 expression in a subgroup including high and low stage data in overall survival data (HR = 0.46, 95% CI = 0.3-0.73, p = 0.0009). (4) Conclusions: This meta-analysis revealed a potential association between high PD-L1 expression and favorable prognosis. However, caution is warranted due to several limitations. Validation via large-scale studies, with mRNA analysis, whole tissue sections, and assessments using FDA-approved antibodies is needed.