HER2 testing: ASCO/CAP guidelines and beyond – implications for South Africa

Abstract

HER2 status in breast cancer has major significance in terms of prognostication and prediction of response to chemotherapeutic agents, as well as being an absolute indicator for the use of trastuzumab. Recent guidelines for the testing and interpretation for HER2 overexpression have resulted in more accurate and concordant results. Excellent concordance between immunohistochemistry and in situ hybridisation techniques can be achieved if these recommendations and guidelines are followed. The recently developed diagnostic techniques of chromagenic in situ hybridisation (CISH) and brightfield dual in situ hybridisation (BDISH) combine the techniques of immunohistochemistry (IHC) and in situ hybridisation (ISH) and will revolutionise HER2 testing.