Assessment Of HER2 Status In Breast Cancer: A Comparison Of Immunohistochemistry, Fluorescence In-situ Hybridization And Chromogenic In-situ Hybridization And Analysis Of Chromosome 17 Polysomy

Objective:Through comparision of HER2 gene status detected by immunohistochemistry(IHC), fluorescence in-situ hybridization(FISH) and chromogenic in-situ hybridization(CISH),to explore the clinical significance of FISH and CISH on detecting gene status of HER2 and the rate and significance of chromosomy 17 polysomy by FISH.Method:Sixty-four paraffin-ebedded breast samples whose pathological types were infiltrating ductal carcinomas were tested by IHC,CISH and FISH for HER2 protein overexpression and HER2 gene status.The rate of chromosome 17 polysomy was also analyzed.Results:Amongst the cases of HER2 protein overexpression(+++) group,the concordant ratios of IHC and CISH,FISH detecting HER2 status were 100%;amongst the cases of HER2 protein overexpression(++) group,the concordant ratios were 95.83%and 91.67%;amongst the cases of HER2 protein overexpression(+/-) group,the concordant ratios were also 100%.One cases in which FISH and CISH were performed yielded the different result,so the general coincident rate was 98.41%.The incidence of chromosome 17 polysomy were 45.16%,45.83%and 11.11%in IHC(+++,++,+/-)three groups,and the total incidence was 40.62%.Chromosome 17 polysomy was correlated to HER2 protein expression(P<0.05 ) and HER2 gene amplification(P<0.05 ).Conclusions:IHC is a preliminary screening method by detecting HER2 protein and whether Herceptin need to be used by clinician.HER2 gene status detected by CISH and FISH have high concordant ratio,through comparing the feature of FISH and CISH,CISH can be seen a more convenience and viable method to detecting status of HER2 gene.When doubling interference of chromosome 17 polysomy,we need to select FISH further.Chromosome 17 polysomy may be related to the prognosis of the patients of breast cancer as HER2 gene amplification.