title: Validity of immunohistochemistry method in predicting HER-2 gene status and association of clinicopathological variables with it in invasive breast cancer patients.
abstract: Human epidermal growth factor receptor-2 is an important and prognostic factors and one of the most targeted proteins in breast cancer's therapy. There is no globally accepted method for determining its status. Here, we aimed to evaluate the immunohistochemistry method validity in predicting HER-2 status by Fluorescence in situ hybridization method and investigate some clinicopathological variables association with HER-2 amplification. A total of 190 HER-2 2+ and 3+ by immunohistochemistry (IHC) invasive breast cancer cases were enrolled in this study. Fluorescence in situ hybridization (FISH) was performed for these cases using FDA criteria and the association between clinicopathological variables and HER-2 status evaluated. Study consisted of 190 invasive breast cancer patients (160 HER-2 2+ and 30 HER-2 3+). HER-2 FISH amplification according to FDA criteria was found 27.5% (44/160 patients) in HER-2 2+ patients and 83.3% (25/30 patients) in HER-2 3+ patients. Tumors with HER-2 amplification were more likely to be ER-negative (51.0% vs 31.2%, p = 0.013) and PR-negative (52.9% vs 27.0%, p < 0.001). This study showed that immunohistochemistry is not a good method for evaluating HER-2 status and decision-making about trastuzumab therapy even with 3+ score patients. However, this result may not be too strong for IHC 3+ cases due to the limited number of these patients in this study.
authors: Persian Gulf Tropical Medicine Research Centre, Bushehr University of Medical Sciences, Bushehr, Iran.
authors: Mohammad Kazzem
authors: MK
authors: Gheybi
authors: Department of Pathology, Isfahan University of Medical Sciences, Isfahan, Iran.
authors: Azar
authors: A
authors: Baradaran
authors: Dr. Mohajeri Laboratory of Isfahan, Isfahan, Iran.
authors: Mohammad Reza
authors: MR
authors: Mohajeri
authors: Department of Epidemiology, Persian Gulf Tropical Medicine Research Centre, Bushehr University of Medical Sciences, Bushehr, Iran.
authors: Afshin
authors: A
authors: Ostovar
authors: School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
authors: Parvaneh
authors: P
authors: Hajalikhani
authors: Department of Immunology, Persian Gulf Tropical Medicine Research Center, Bushehr University of Medical Sciences, Bushehr, Iran.
authors: Shokrollah
authors: S
authors: Farrokhi
mesh_terms: D000328:Adult; D000368:Aged; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000473:pathology*; D005260:Female; D015870:Gene Expression; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence; D008875:Middle Aged; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human
keywords: Invasive breast cancer; fluorescent in situ hybridization; human epidermal growth factor receptor-2; immunohistochemistry; prediction