Journal of Clinical and Diagnostic Research (Oct 2024)
Clinicopathological and Prognostic Significance of PD-L1 Expression in Male and Female Breast Carcinoma Cases: A Cohort Study
Abstract
Introduction: Male Breast Carcinoma (MBC) is rare compared to Female Breast Carcinoma (FBC) and differs significantly in tumour biology. The expression of Programmed Death receptor-1 (PD-1) and its ligand, Programmed Death-ligand 1 (PD-L1), is extensively studied in FBC for the implementation of newer immunotherapies; however, the role of these immunomarkers in MBC is still not well understood. Aim: To evaluate the expression of PD-L1 in MBC and FBC patients and to assess its clinicopathological and prognostic significance. Materials and Methods: This cohort study was conducted in the Department of Pathology of IPGMER and SSKM Hospital in Kolkata, West Bengal, India, in collaboration with the Department of Surgery over a period of 4 years from January 2020-December 2023. Histopathological examinations were performed on 204 mastectomy specimens from male and female breast cancer patients. Immunohistochemistry for PD-L1, Oestrogen Receptor (ER), Progesterone Receptor (PR), and HER2/neu was conducted on Formalin-fixed Paraffin-embedded (FFPE) tissue. The clinicopathological parameters were analysed alongside PD-L1 expression in breast carcinoma for both genders. Kaplan’s-Meier graphs were plotted for survival analysis. The Statistical Package for the Social Sciences (SPSS) version 29.0 was used for data analysis, with a significance threshold set at a p-value of <0.05 (Chi-square test). Results: The age range was 48 to 65 years in the male population and 30 to 74 years in the female population. A total of 204 cases were included in the study, with 50 cases of MBC and 154 cases of FBC. PD-L1 expression was observed in 48% of MBC cases and in 52.59% of FBC cases. No significant difference in PD-L1 expression was noted between MBC and FBC (p-value=0.572). MBCs exhibited different biological characteristics, including a predominance in older age, smaller tumour size, and more frequent luminal molecular types compared to FBC, with the luminal A subtype being the most common in MBC (38%), while the triple-negative subtype was the most common in FBC (35%). Overall survival analysis also did not demonstrate significant survival advantages in PD-L1 positive cases (p-value=0.491 for MBC cases and 0.128 for FBC cases). Conclusion: PD-L1 expression in MBC does not differ significantly from that in FBC. Furthermore, PD-L1 expression did not confer significant survival advantages in either MBC or FBC cases.
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