Contrast study of HER-2 status in breast cancer by immunohistochemistry and fluorescence in situ hybridization

Obsjective To research the concordance between immunohistochemistry(IHC) and fluorescence in situ hybridization(FISH) assessment for HER-2 status in breast cancer patients.Methods Detecting the HER-2 gene amplification and polysomy 17 by FISH and HER-2 protein status by IHC in 50 cases of breast cancers,analyzed the concordance of these two tools and the relationship between polysomy 17 and HER-2 protein status.Results The concordance of FISH in the cases of IHC3+,2+,0/+ were 92.9%,70.0% and 80.8% respectively.The total concordance of the two tools in 50 cases was 82.0%(kappa=0.640).The polysomy 17 was strongly associated with HER-2 protein(P0.05).Conclusions FISH is a valuable tool with high accuracy and stability for the test of HER-2 gene amplification.The concordance between FISH and IHC is good in IHC3+ cases,and the discordance is mainly in IHC2+ and IHC0/+ cases.The IHC can be used as a preliminary screening method,FISH is necessarily used to determinate the HER-2 gene status in breast cancer patients with IHC 2+ and 0/+.