Immunohistochemical detection of axillary lymph node micrometastases in node negative breast cancer patients using cytokeratin and epithelial membrane antigen

BACKGROUND AND OBJECTIVE: The study was conducted to detect occult metastases in lymph node negative breast cancer patients using cytokeratin (CK) and epithelial membrane antigen (EMA) immunohistochemistry (IHC) and correlate this with primary tumor size and grade. MATERIALS AND METHODS: A total of 32 cases including 12 prospective and 20 retrospective cases of axillary lymph node negative breast cancer were studied. CK and EMA IHC were performed to detect micrometastases. RESULTS: Axillary lymph node metastases were detected in 18.75% of previously node negative cases using CK and EMA IHC. CK was found to be more sensitive for detection of metastases compared to EMA. A highly significant correlation was observed between tumor grade and axillary lymph node metastases detected by CK and EMA. However, no significant correlation was found between tumor size and axillary lymph node metastases detected by IHC. CONCLUSION: In the present study, there was an increase of 18.75% in the occult metastases detection rate using CK and EMA. To conclude, IHC detection of occult metastases should be done using CK in all axillary node negative cases, especially in T1 and T2 stage tumors.