[HER-2 overexpression and gene amplification of advanced breast cancers determined by fluorescence in situ hybridization in fine needle aspiration specimens].

Objective To explore the feasibility of testing HER-2 expression and gene amplification in fine needle aspiration specimens of advanced breast cancers,and to benefit the patients receiving targeted drug therapy.Methods Liquid-based cytology specimens by fine needle aspiration of 49 breast cancer cases were used in this study.The expression of HER-2 protein was detected by immunocytochemistry (ICC) and the gene amplification was assessed by fluorescence in situ hybridization (FISH).All the 49 cases had overexpression of HER-2 protein marked as + + or + + + in immunohistochemistry (IHC),and had corresponding FISH results in formalin-fixed,paraffin-embedded (FFPE) tissue samples.Results FNA samples in all the 49 cases were tested by FISH,and showed a complete agreement with the FISH results in the histological specimens (kappa =1.0).Of the 49 cases,33 had HER-2 gene amplification in FFPE samples.So do that in FNA samples.Both had an amplification rate of 67.3％.Among the 33 cases with HER-2 gene amplification,26 had an ICC score of + + + (78.8％).The conformity rate was 78.8％.Of the 33 cases,29 had an IHC score of + + + (87.9％).Its conformity rate was 87.9％.The difference between the ICC and IHC results was statistically not significant (P =0.322).Among the 16 cases with negative gene amplification by both ICC and IHC,15 cases showed HER-2 protein expression as 0/+,and another one case was not counted because there was not enough cells.Of the 16 cases,15 had an IHC score of + + and one of + + +.To take the FISH results as gold standard,ICC results had a high sensitivity (87.9％) and specificity (100.0％).Conclusions FISH in FNA samples can be used in the clinic to test HER-2 gene amplification and overexpression in breast cancers,with a high sensitivity and specificity in ICC.Our data support the use of FISH and ICC analysis to determine HER-2 status on FNA specimens in patients with advanced breast cancer and recurrence or metastatic tumors.When ICC score is + + +,it indicates that there is a HER-2 gene amplification by FISH. Key words: Breast neoplasms;  Fine needle aspiration;  Immunocytochemistry;  In situ hybridization;  Human epidermal growth factor receptor-2