Assessment Of HER2Status In Breast Cancer:Comparison Of Immunohistochemistry Assay Withfluorescence In Situ Hybridisation Assay

Purpose:Through comparison of immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH) to evaluate the clinical usefulness of the two assays for HER2gene and protein measurements. Through comparison of2013and2007ASCO/CAP HER2testing guidelines in breast cancer to explore the clinical impact of guideline changement.Method:An immunohistochemistry (IHC) assay which measures the Her-2protein, was compared with an fluorescence in situ hybridization (FISH) assay, which measures the HER2gene in a cohort of377formalin fixed, paraffin-embedded breast cancer specimens.Compare2013and2007ASCO/CAP HER2testing guideline FISH results in377invasive breast cancer specimens to calculate the ratio of people affected.Results:Among the cases of IHC3+group, the concordant ratio of FISH detecting was98.2%(56/57); In IHC2+group, the concordant ratio was43.1%(25/58); Among the cases of IHC+and IHC0group, the concordant ratio was95.4%(250/262). The degree of concordance (kappa) of two assays was0.899.39cases was influenced by the2013ASCO/CAP HER2testing guidline update,acounting for10.3%of the total.Conclusion:IHC can be used as a screening method by detecting HER2protein. IHC2+cases must be detected by FISH while IHC0/1+or IHC3+cases may not.2013ASCO/CAP breast cancer HER2testing guidelines broaden FISH HER2positive standard.Some patients may be affected by this guideline changement.