- Paper Report
- Open Access
Her-2/neu and topoisomerase IIaexpression in primary and metastatic breast cancer
- Fatima Cardoso1
© Biomed Central Ltd 2001
- Received: 13 September 2001
- Accepted: 13 September 2001
- Published: 1 December 2001
- Breast cancer, HER-2, topoisomerase II-a, primary metastases
The HER-2/neu oncogene and, more recently, the topoisomerase II-a gene have been implicated in the prediction of response to chemotherapy in breast cancer. HER-2 amplification is also a prerequisite for therapy with trastuzumab (HerceptinR). Determination of HER-2 and topoisomerase II-a gene amplification is usually done in primary tumour samples. However, therapy strategies used to target metastases may show reduced efficacy, as metastatic cancers may be biologically different to primary tumours.
The authors analysed HER-2 and topoisomerase II-a gene amplification in 46 breast primary tumours and its metastases, using immunohistochemistry (IHC) and DNA in situ hybridisation techniques. HER-2 amplification was seen in 28% (13 patients) of primary tumours and was always associated with amplification in its metastases; no metastases with HER-2 amplification were seen without amplification in the primary tumour. The gene status of topoisomerase II-a (amplification/deletion/unaltered) remained unchanged in 10 of the 13 HER-2 positive tumours; in three cases, the predominant cell population in metastatic tissue was present only as a subpopulation in the primary tumour. The authors conclude that amplification of HER-2 in the primary tumour reflects its status in the metastases, and that only minor discrepancies exist, between primary and metastatic tissue, regarding topoisomerase II-a gene status.
FISH, chromomeric in situ hybridisation (CISH), IHC