Herceptin Research Today is a free monthly online journal that collates and summarizes the latest research about Herceptin, including details on side-effects, breast cancer, treatment, therapy.

Comparison between immunohistochemistry and chromogenic in situ hybridization in assessing HER-2 status in breast cancer.

Todorović-Raković N, Jovanović D, Nesković-Konstantinović Z, Nikolić-Vukosavljević D

Institute of Oncology and Radiology of Serbia, Belgrade, Serbia and Montenegro. todorovicn@ncrc.ac.yu

Human epidermal growth factor receptor-2 (HER-2) is usually determined as a potential target for breast cancer therapy. The purpose of the present study was to compare chromogenic in situ hybridization (CISH) with immunohistochemistry (IHC) in determination of HER-2 status, in metastatic breast cancer patients screened for the clinical study of chemotherapy +/- herceptin. It was possible to assess both CISH and IHC in 56 cases, using CISH Detection Kit (Zymed) and HercepTest (DakoCytomation), respectively. HER-2 was amplified by CISH in 32 cases (57%) while 33 (59%) were HER-2-positive by IHC. A concordance between HER-2 status determined by CISH and IHC was noted in 43 of 56 cases (77%; P = 0.00008). Gene amplification was observed in 6/16 cases (37.5%) in IHC-negative subgroup (1+), while no amplification was observed in 5/10 cases (50%) in the IHC-positive subgroup (2+). These results suggest that there was a greater heterogeneity on the genetic level and that simple IHC classification was not sufficient. It is suggested that CISH could be considered as a useful additional method to IHC in determining HER-2 status in breast cancer patients, with a recommendation for testing not only the 2+ but also the 1+ subgroup of patients.

Published 9 June 2005 in Pathol Int, 55(6): 318-23.
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