It has been reported that up to 40% of HER2+ breast cancers display a co-amplification of TOP2A and ERBB2 genes [15], which has been investigated as a predictive marker of anthracycline efficacy [15,16,17,18,19] in HER2+ breast cancers, with controversial results [20,21,22,23]. The gene discussed is ERBB2; the disease is breast cancer.