Evaluation of Immunohistochemical Profile of Breast Cancer for Prognostics and Therapeutic Use

INTRODUCTION: Breast cancer is leading cancer in women, and the incidence of breast cancer in India is on the rise. The most common histologic type of breast cancer is infiltrating ductal carcinoma. Prognostic and predictive factors are used in the management of breast cancer. Estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor-2 (HER2/neu) are immunohistochemical markers of prognosis as well as predictors of response to therapy. AIMS AND OBJECTIVES: The study was conducted to evaluate ER, PR, and HER2/neu expressions in invasive ductal carcinomas of the breast by immunohistochemistry, to explore the correlation of these markers to each other and to various clinicopathological parameters: age of the patient, histological grade, tumor size, and lymph node metastasis. MATERIALS AND METHODS: This prospective study was conducted on 100 cases of infiltrating ductal carcinoma. Slides were prepared from blocks containing cancer tissue, and immunohistochemical staining was done for ER, PR, and HER2/neu expressions. Interpretation of expressions was done using Allred scoring system for ER/PR and the American Society of Clinical Oncology/College of American Pathologists guidelines for HER2/neu. Statistical analysis was performed to determine the statistical significance by applying Chi-square test. RESULTS: Majority of tumors were ER and PR positive and HER2/neu negative. ER and PR correlated significantly with age, tumor size, and tumor grade; whereas, HER2/neu correlated significantly with tumor size only. No association was seen with axillary lymph node metastasis. ER and PR expression correlated with each other, but none correlated with HER2/neu. CONCLUSIONS: As the majority of the tumors are ER, PR positive and since ER and PR correlate with each other as well as with age, tumor size, and grade. Therefore, routine assessment of hormone receptors is recommended for prognostic and therapeutic information in breast cancer cases.