DOI: 10.6084/m9.figshare.28855550.v2
title: <b>Expression of Programmed Death Ligand-1 in Molecular subtypes of Breast carcinoma and correlation with clinicopathological parameters</b>

description: Background: Breast Cancer (BC) is one of the most common malignant neoplasms and leading cause of cancer mortality in womenClick or tap here to enter text.. Being a complex and heterogenous disease, it can be subtyped based on the expression of various molecules as detected by Immunohistochemistry (IHC) (2). The specific targeting of the Programmed Death-1/Programmed Death Ligand-1 axis is currently the recommended choice of care in many advanced tumours. Objective: This study aims to assess the expression of Programmed Death Ligand-1 in Breast carcinoma patients and correlate with prognostic clinicopathological parameters. Methods: All histomorphologically diagnosed Invasive Breast carcinomas were retrieved from the Pathology department archives and demographics details and immunohistochemical profile of the tumour (ER, PR, Her2 neu and Ki-67 index), were collected from the medical records and patient case record files. Results: Eighty patients (n=80) with a histopathological and immunohistochemical report of primary Invasive breast carcinoma were obtained from the archives of Department of Pathology, Kasturba Medical College. Over the course of this study, 80 specimens of modified radical mastectomy specimens with a histopathological diagnosis of Invasive breast carcinoma were considered. The patients ranged from ages 23 to 73 years, with majority of them (35%) presenting in their 5th decade of life (50-59 years). Out of the cases studied, the most common molecular subtype was Luminal A with 26 (32%) cases followed by 23 (29%) cases of Her 2 Enriched, 16 (20%) cases of Luminal B with Triple negative subtype being the least of all at 15 (19%) cases. The demographic Mean age at diagnosis was 52 ± 10.4 years, showing a range from 23 to 73 years. The mean greatest dimension of the tumour was 4.5 ± 2.68 cm, with the maximum being 17 cm in one case of invasive carcinoma of breast. The mean number of lymph nodes involved was 4, ranging from 0 to 31 lymph nodes involved. Necrosis was seen in 35 (43.8%) cases and was significantly associated with higher tumour grades i.e grade 2 and 3 (p value&lt;0.05). Grade 3 morphology was seen in 19, Grade 2 morphology in 44 and Grade 1 morphology in 17 cases. 46 patients had disease with pathological stage 2 at presentation, 16 at stage 3 and 9 each at stage 1 and stage 4. Invasive breast cancer, no special type was the most reported histopathological subtype in 77 cases (96.3%). Luminal A was the most common molecular subtype with 26 cases (32.5%) followed by Her-2 Enriched in 23 cases (28.75%), Luminal B in 16 cases (20%) and Triple negative in 15 cases (18.75%). Conclusion: In summary, this study provides valuable insights into the expression of PD-L1 in breast carcinoma and its association with clinicopathological factors in a South Indian cohort. The findings emphasize the potential of PD-L1 as a prognostic marker and a therapeutic target, particularly in TNBC. The high PD-L1 expression in immune cells suggests that immunotherapy could be a viable treatment option for a significant subset of breast cancer patients. Further research with standardized methodologies and larger, diverse cohorts is crucial to fully understand the role of PD-L1 in breast cancer and optimize its clinical application.