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Disease Markers
Volume 26, Issue 4, Pages 171-180

Metastatic Breast Cancer Survival according to HER2 and Topo2a Gene Status

N. Todorović-Raković,1 Z. Nešković-Konstantinović,2 and D. Nikolić-Vukosavljević1

1Department of Experimental Oncology, Institute for Oncology and Radiology of Serbia, Belgrade, Serbia
2Department of Clinical Oncology, Institute for Oncology and Radiology of Serbia, Belgrade, Serbia

Received 19 August 2009; Accepted 19 August 2009

Copyright © 2009 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


The aim of this study was to determine the relationship between amplification of HER2 (Human epidermal growth factor receptor 2) and Topo2a (topoisomerase 2a) and their influence on prognosis in metastatic breast cancer (MBC) patients. Amplification of both HER2 and Topo2a genes was determined by chromogenic in situ hybridization (CISH) in primary tumor tissue of 71 MBC patients. Starting point for follow-up was the time of diagnosis of metastatic disease. Although there was significant correlation between HER2 amplification and Topo2a alterations, Topo2a amplification was not strictly related to HER2 amplification. Follow-up of patients showed that there was no difference in MBC survival between HER2-nonamplified and HER2-amplified patients for subgroup as whole, but there was significant difference in MBC survival between patients with and without Topo2a amplification. HER2 amplification showed prognostic value in subgroups of patients, as well as Topo2a. Combination of these two genes with different status (nonamplified, amplified, coamplified) indicated that they might have additive effect. Also, it has been shown that Topo2a-amplified cases have poorer survival than Topo2a-nonamplified, when treated with CMF therapy.

Topo2a amplification seems to be more promising biomarker of MBC survival, than HER2, and potential marker of resistance to CMF therapy.