Immunohistochemical Expression of Programmed Death Ligand 1 (PD-L1) and Its Correlation with Clinicopathological Parameters in Breast Carcinoma
Monika Pawar *
Department of Pathology, BLDE (DU), Shri B. M. Patil Medical College, Hospital and Research Centre, Vijayapura, Karnataka, India.
Satish Arakeri
Department of Pathology, BLDE (DU), Shri B. M. Patil Medical College, Hospital and Research Centre, Vijayapura, Karnataka, India.
*Author to whom correspondence should be addressed.
Abstract
Aims: Breast carcinoma (BC) is the leading cause of tumor burden, with an incidence of 11.8%. The programmed cell death protein 1(PD-1)/programmed death ligand 1 (PD-L1) pathway represents an adaptive immune resistance mechanism that tumor cells exert. Recent updates in the treatment modality of breast carcinoma indicate that the use of anti-PD-L1 therapy will help treat advanced breast carcinoma. This study aimed to evaluate the immunohistochemical (IHC) expression of the PD-L1 in breast carcinoma and to analyze the correlation between the PD-L1 and various clinicopathological factors.
Study Design: A hospital-based cross-sectional study.
Place and Duration of Study: Department of Pathology, BLDE(DU). Shri B.M. Patil Medical College, Hospital, and Research Center, Vijayapura. Between 1st May 2023 to 31st December 2024.
Methodology: The study was conducted on fifty invasive breast carcinoma cases. Tumor samples were assessed via routine microscopy and graded using the Bloom-Richardson system. IHC was performed for PD-L1 and estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2/neu (HER2/neu) status. PD-L1 scoring was performed using the combined positive score (CPS). PD-L1 expression was then correlated to clinicopathological factors including age, tumor size, histologic type and grade, lymph node status, and pTNM stage.
Results: PD-L1 expression was seen in 14 out of 50 cases (28.0%). Expression of PD-L1 showed a statistically significant correlation with HER2/Neu (p = 0.03). The expression of PD-L1 is not statistically significant with other clinicopathological parameters. Hence, PD-L1 may not be a robust prognostic marker based on current evidence.
Conclusion: Standardized PD-L1 immunohistochemistry reporting ensures reliable evaluation of breast carcinoma. Consistent and accurate PD-L1 assessment could significantly impact the application of novel targeted immunotherapies in treating breast carcinoma.
Keywords: Breast carcinoma, PD-L1, prognosis, clinicopathological