ERBB2 FISH study

ASCO/CAP criteria

The novel ASCO/CAP criteria for assessing immunohistochemical results in HER 2 testing reduce the false positive rate of HER2.

First-line testing with immunohistochemistry may obscure false positive and false negative test results.

In heterogeneous carcinomas even fluorescence in situ hybridization may not succeed in a correct evaluation of HER2.

HER2-overexpressed/amplified breast carcinomas

Accurate assessment of the human epidermal growth factor receptor 2 (HER2) of invasive breast cancer is essential to treatment decisions since the advent of targeted therapy with the humanized monoclonal antibody trastuzumab and the dual tyrosine kinase inhibitor lapatinib.

In the literature, the percentage of HER2-overexpressed/amplified breast carcinomas range from 3% to 30%.

The HER2 positivity rate may be as low as 9%.

References

 Confirmation of a low HER2 positivity rate of breast carcinomas - limitations of immunohistochemistry and in situ hybridization. Vogel UF. Diagn Pathol. 2010 Jul 29;5:50. PMID: 20670419 [Free]

 Breast cancer evaluation by fluorescent dot detection using combined mathematical morphology and multifractal techniques. Reljin B, Paskas M, Reljin I, Konstanty K. Diagn Pathol. 2011 Mar 30;6 Suppl 1:S21. PMID: 21489192 [Free]

 Fluorescence in situ hybridization (FISH) as primary methodology for the assessment of HER2 Status in adenocarcinoma of the breast: a single institution experience. Tubbs RR, Hicks DG, Cook J, Downs-Kelly E, Pettay J, Hartke MB, Hood L, Neelon R, Myles J, Budd GT, Moore HC, Andresen S, Crowe JP. Diagn Mol Pathol. 2007 Dec;16(4):207-10. PMID: 18043283