Diagnostic Value of Immunohistochemistry Studies in Breast Carcinoma and Molecular subtypes

Abstract

Immunohistochemical analysis plays a pivotal role in the diagnosis of breast cancer, enabling not only tumor verification but also the determination of its molecular-biological profile. The assessment of estrogen receptor (ER) and progesterone receptor (PR) expression, HER2/neu status, and the Ki-67 proliferation index forms the basis for classifying tumors into Luminal A and B, HER2-positive, and triple-negative subtypes. Each of these subtypes is characterized by a distinct disease course, prognosis, and response to targeted therapy, endocrine therapy, and chemotherapy. Thus, immunohistochemistry is not merely an ancillary method but an essential tool for a personalized approach to patient care, facilitating accurate risk stratification and the selection of the optimal therapeutic strategy.