Several findings, such as cancer development, cancer stage, oestrogen receptor (ER) and progesterone receptor (PR) expression, human epithelial growth factor receptor 2 (HER2) gene amplification, p53 overexpression, and BRCA1 and BRCA2 mutations, are taken into account in the development, treatment, and management of breast cancer [3]. This evidence concerns the gene ERBB2 and cancer.