title: Comparison between immunohistochemistry and chromogenic in situ hybridization in assessing HER-2 status in breast cancer.
abstract: 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.
authors.affiliation: Institute of Oncology and Radiology of Serbia, Belgrade, Serbia and Montenegro. todorovicn@ncrc.ac.yu
authors.forename: Natasa
authors.initials: N
authors.lastname: Todorović-Raković
authors.forename: Danica
authors.initials: D
authors.lastname: Jovanović
authors.forename: Zora
authors.initials: Z
authors.lastname: Nesković-Konstantinović
authors.forename: Dragica
authors.initials: D
authors.lastname: Nikolić-Vukosavljević
mesh_terms: D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D017403:In Situ Hybridization / Q000379:methods; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis* / Q000235:genetics
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases