Expression of Programmed death ligand-1(PD-L1)and Forkhead Bos P3 (FOXP3) in HER 2 NEU positive breast carcinoma and its association with clinico pathological parameters

Title: Expression of PD-L1 and FOXP3 in HER2-positive Breast Carcinoma and its Association with Clinicopathological Parameters

Summary:

Breast carcinoma is the most common malignancy among women worldwide, with HER2-positive subtype representing an aggressive variant associated with poor prognosis and limited response in a subset of patients despite targeted therapies. The tumour immune microenvironment plays a crucial role in disease progression and treatment response, with Programmed Death-Ligand 1 (PD-L1) and Forkhead Box P3 (FOXP3) identified as key immunoregulatory markers. PD-L1 mediates immune evasion by inhibiting T-cell activation, while FOXP3 marks regulatory T cells that suppress antitumour immunity. Co-expression of these markers may signify an immunosuppressive phenotype contributing to therapeutic resistance.This cross-sectional study aims to evaluate the expression of PD-L1 and FOXP3 in HER2-positive post-chemotherapy breast carcinoma and correlate their expression with clinicopathological parameters including tumour grade, lymph node status, and size. Immunohistochemical analysis will be performed on resected specimens using monoclonal antibodies against PD-L1 and FOXP3, and results will be analyzed statistically.The findings are expected to enhance understanding of the immune landscape of HER2-positive breast carcinoma and may identify biomarkers predictive of therapeutic response and prognosis, particularly relevant for optimizing management in resource-limited settings such as India.