Whereas two studies in primary BC demonstrated successful single-cell tumor elimination in blood and bone marrow by anti-HER2 treatment [30, 31], the NSABP B47 and the Treat-CTC trial failed to confirm the hypothesis that adjuvant trastuzumab can benefit women with HER2 non-amplified early BC [33, 34]. This evidence concerns the gene ERBB2 and neoplasm.