2. nd hypothesis : Patients with ER negative/HER-2 non amplified tumors: In this subset of patients, almost no topo II a gene aberrations will be found based on previous data discussed above. However, recent data reported by C. Sotiriou et al using cDNA microarrays, suggest that in this subset of ER-negative HER-2 negative tumors, also defined as the basal-like subset, two distinct subgroups can be identified (i.e. basal-like 1 and 2). While basal-like 1 tumors show a high proliferation rate and high levels of topo II a RNA, basal-like 2 tumors have a moderate-low proliferation rate and normal levels of topo II a RNA. We hypothesize that the topo II a RNA overexpression in basal-like 1 tumors is not related to topo II a gene amplification because no concomitant HER-2 gene amplification is reported in this subset of tumors. The second study hypothesis is that in ER negative/HER-2 non amplified tumors with topo II a protein overexpression, a 2.5 fold increase in pCR rate will be observed, as opposed to the pCR rate in tumors with low topo II a protein content.