Investigation of HER-2 status evaluated by both IHC and FISH approaches in 278 cases of invasive breast carcinoma

Objective Breast cancer is the most common malignancy in the women.If the patients with HER-2 positive have invasive breast carcinoma,they can obtain beneficial results from the targeting therapy by Herceptin.Therefore,accurate detection the HER-2 gene status is the key point to select the candidates for Herceptin treatment.At present,the IHC and FISH techniques are the most popular methods used to evaluate the HER-2 status.Even though there is high concordance rate between the 2 methods,the discrepancies in positive rate of HER-2 between these two different approaches exist obviously.This research serves to investigate the concordance rate between the two different methods to test the HER-2 status,respectively.Methods Both IHC and FISH techniques were performed separately in 278 cases to detect the status of HER-2 protein expression and gene amplification.Statistically,SPSS11.5 software was applied to analyse the results obtained in both methods.Results The total concordance rate of HER-2 between IHC and FISH trials was 83.9%,with Kappa of 0.650(P0.001).Forty-four among 130 cases(33.8%) with ++ IHC and 5/54(9.3%) with 0 or + IHC cases were positive in FISH.Three among the 94(20.2%) with +++ IHC cases were negative in FISH,and 3 of the 130 cases with ++ IHC were equivocal in FISH.Conclusions The concordance rate in our investigation between IHC and FISH of HER-2 was 83.9%,and FISH could get satisfying result in most of the ++ IHC cases.However,comprehensive consideration should be taken together with other testing results in those few equivocal cases.