Concordance Between FISH Analysis of Her-2/Neu Gene in Breast Duct Carcinoma and Corresponding Axillary Nodal Metastases: Egyptian National Cancer Institute Experience.

Abstract

Breast cancer is a major health problem in Egypt. Her-2/Neu gene is routinely assessed for all breast cancer patients primarily by immunohistochemistry. At National Cancer Institute (NCI), Cairo University, Flourescence In Situ hybridization (FISH) analysis of Her-2/Neu gene is carried out for Her-2/Neu score 2 and for some cases of score 3 (particularly those assessed outside NCI). The test is performed essentially on the primary tumor. However, some situations require testing on corresponding lymph node metastases. There is a debate about the concordance between Her-2/Neu status in the primary tumor and synchronous lymph node metastases in various studies. The aim of this study was to test for the concordance between Her-2/Neu status in the primary breast tumor and corresponding axillary nodal metastases. This is a retrospective study in which FISH analysis of Her-2/Neu was carried out simultaneously on archived material of 50 cases previously diagnosed as invasive duct carcinoma and the corresponding nodal metastases from the Pathology Department, NCI. There was complete concordance between Her-2 status in the primary tumor and the corresponding axillary lymph node metastatic deposits in which Her-2 was amplified in 44% of the studied cohort of Egyptian patients. Her-2/Neu gene assessed by FISH analysis on synchronous lymph node metastases is strongly correlated with the primary tumor. Hence, it is justified to carry out the Her-2/Neu test on synchronous lymph nodes to decide on whether to carry out anti-Her-2/Neu target therapy. Further studies on other metastatic sites is recommended.