Abstract
The purpose of this study was to evaluate amplification of topoisomerase IIalpha (TOP2A) and HER2 genes as predictors of response to chemotherapy in advanced breast cancer. Gene copy number of TOP2A and HER2 were analysed with chromogenic in situ hybridization (CISH) on paraffin-embedded tissue sections from the primary tumour of 85 patients treated with anthracycline containing chemotherapy. TOP2A gene amplification was present in 14 (16%) and HER2 gene amplification in 38 (45%) of the primary tumours. Two of the 14 cases with TOP2A amplification were amplified without concurrent HER2 amplification. Neither TOP2A nor HER2 gene amplification were significantly associated with response to chemotherapy (p = 0.35 and p = 0.49, respectively).