Evaluation Of Hormone Receptors And Ki-67 In Tumor And Peritumoral Region Of Breast Carcinoma

Background: Hormonal receptors and proliferative indices such as estrogen receptor (ER), progesterone receptor (PR), HER2neu, and Ki-67 are essential in prognostic and therapeutic stratification of breast carcinoma. While tumor marker evaluation is routine, the adjacent peritumoral region is less studied despite its potential biological significance. Aim: To evaluate and compare the expression of ER, PR, HER2, and Ki-67 in tumor and peritumoral regions of breast carcinoma and correlate findings with histological grade and lymph node status. Materials and Methods: This retrospective-prospective study included 43 biopsy-confirmed breast carcinoma cases over a four-year period. Immunohistochemistry was performed for ER, PR, HER2, and Ki-67 on both tumor and peritumoral areas. Molecular classification was done based on IHC profile. Statistical correlation was assessed using appropriate tests. Results: ER and PR positivity was significantly higher in tumor tissue compared to peritumoral areas. Ki-67 index was also higher in tumor regions. HER2 showed similar expression in both zones. Luminal A was the most frequent molecular subtype, followed by basal-like and HER2-enriched subtypes. A significant association was noted between high Ki-67 index and higher tumor grade and nodal involvement (p < 0.05). Conclusion: Hormonal and proliferative marker expression in peritumoral tissue may offer additional prognostic insight, especially in borderline cases. Integrating peritumoral evaluation with conventional tumor analysis could improve risk stratification and early detection of field changes.