Comparison of Her-2 Detections by Fluorescence in situ Hybridization(FISH) and by Immunohistochemistry(IHC) in Breast Cancer

[Purpose] To investigate the difference of Her-2 expression detected by fluorescence in situ hybridization(FISH) and by immunohistochemistry(IHC) in breast cancer.[Methods] Both IHC and FISH techniques were performed to detect Her-2 gene amplification and Her-2 protein expression respectively in 508 samples with breast cancer.[Results] Among 104 cases(20.47%) with 0/+ Her-2 protein expression detected by IHC,13 cases(2.56%) were Her-2 gene amplification detected by FISH;89 cases(17.52%),non-amplification;2 cases(0.39%),suspicious.Among 245 cases(48.23%) with ++ Her-2 protein expression,121 cases(23.82%) were Her-2 gene amplification;120 cases(23.62%),non-amplification;4 cases(0.79%),suspicious.Among 159 cases(31.30%) with +++ Her-2 protein expression,137 cases(2.97%) were Her-2 gene amplification;22 cases(4.33%),non-amplification.[Conclusion] Detecting the amplification of Her-2 gene with FISH may be helpful to know Her-2 gene status for treatment decision in breast cancer patients with positive Her-2 expression ++～+++ by IHC.