Indeed, ErbB2 amplification is used as an independent prognostic indicator for overall survival and time to relapse in breast cancer, where the increased ErbB2 expression level correlates positively with the presense of cells in S-phase, tumor size, grade, aneuploidy, metastasis to the lymph nodes, and resistance to endocrine therapy [11,13]. This evidence concerns the gene ERBB2 and breast carcinoma.