HER-2eu amplification detected by fluorescence in situ hybridization in fine needle aspirates from primary breast cancer.

摘要

BACKGROUND: The HER-2eu gene is amplified in 20-30% of human breast cancers and has been shown to have prognostic and predictive value for treatment with chemotherapy, hormone therapy and antibodies against the HER-2eu domain (trastuzumab). The aim of our study was to evaluate the reliability of HER-2eu determination by fluorescence in situ hybridization (FISH) on fine-needle aspirates (FNAs) from primary breast cancer patients by comparison with the results obtained by FISH and immunohistochemistry (IHC) on the corresponding histological sections. MATERIALS AND METHODS: HER-2eu amplification was determined by FISH on 66 breast cancer FNAs. Twenty-three and 36 corresponding formalin-fixed, paraffin-embedded sections were assayed by FISH and by IHC, respectively, in order to detect HER-2eu amplification and HER-2eu protein expression. RESULTS: Twenty-seven per cent (18/66) of breast cancer FNAs showed amplification of HER-2eu by FISH. Paired results by FISH cytology and FISH histology were available in 22 cases. Concordance was 91% (20/22). Paired results by FISH cytology and IHC were available in 36 cases. Concordance was 92% (33/36). Eighteen of 66 breast cancer FNAs were also submitted to flow cytometric DNA analysis. None of the diploid cases showed HER-2eu amplification by FISH. Six out of the eight aneuploid cases were amplified and two were polysomic. CONCLUSIONS: HER-2eu gene amplification can be reliably estimated by FISH on breast cancer FNAs and a good correlation has been found between FISH and IHC results from the corresponding histological sections.