Assessment of HER2/neu status in breast cancer: a comparison of immunohistochemistry, fluorescence insitu hybridization and chromogenic insitu hybridization

Objective Through comparision of HER2/neu status detected by immunohistoehemistry (IHC),fluorescence insitu hybridization(FISH)and chromogenic insitu hybridization(CISH),to explore the clinical significance of FISH and CISH on detecting gene status of HER2.Methods Sixty-four paraffinembedded breast samples whose pathological types were infiltrating ductal carcinomas were tested by IHC for HER2 protein overexpression and CISH,FISH for HER2 gene status.The rate of chromosome 17 polysomy was also analyzed.Results Among the cases of HER2 protein overexpression(+++)group,the concordant ratios of IHC and CISH.FISH detecting HER2/neu status were 100%.Among the cases of HER2 protein overexpression(++)group,the concordant ratios were 95.83%and 91.67%.Among the cases of HER2 protein overexpression(+/-)group,the concordant ratios were also 100%.One case in which FISH and CISH were performed yielded the different results.so the general coincident rate was 98.41%.The incidence of chromosome 17 polysomy Was 45.16%,45.83%and 11.11%in three IHC(+++,++,+/-)groups,and the total incidence was 40.62%.ConclusionIHC is a preliminary screening method;HER2 gene status detected by CISH and FISH have high concordant ratio,CISH is a more convenience and viable method to detect HER2/neu status,when doubling interference of fichromosome 17 polysomy,we need to select FISH further. Key words: Breast neoplasms; Gene,erbB-2; Immunohistochemistry; Insitu hybridization,fluorescence; Insitu hybridization,chromogenic