Gene expression profiling of breast cancer patients treated with docetaxel, doxorubicin, and cyclophosphamide within the GEPARTRIO trial: HER-2, but not topoisomerase II alpha and microtubule-associated protein tau, is highly predictive of tumor response

Gene expression analysis in breast cancer patients undergoing neoadjuvant chemotherapy is an interesting tool for identification of gene signatures and new markers to predict tumor response. However, the detection of predictive markers strongly depends on the drugs used in the specific therapeutic setting. There is growing evidence that topoisomerase II-alpha (TOPO IIα) is a marker for anthracycline-, and microtubule-associated protein tau (MAPT) for taxane sensitivity. HER-2 has been described as a marker of both anthracycline and taxane sensitivity. We performed gene expression profiling of 50 patients within the GEPARTRIO study, an anthracycline and taxane neoadjuvant chemotherapy trial. Here we investigate the predictive value of TOPO IIα, MAPT and HER-2 mRNA expression for pathological complete response (pCR) in this setting. Interestingly, HER-2 gene expression was strongly predictive of pCR (P=0.017) as well as overall response (P=0.037) and clinical complete response (cCR, P=0.050). In contrast, for both TOPO IIα and MAPT no correlation with pCR was observed in our sample group.