The expression of miR-34a, BRCA1, BRCA2 and p53 in Estrogen Receptor (ER), Progesterone Receptor (PR), and Human epidermal growth factor receptor 2 (HER2/neu) female patients in the different subtypes and clinical stages of breast cancer, pre- and post-chemotherapy (Mean ± SD). The numbers between brackets represent the number of patients. This evidence concerns the gene ERBB2 and breast cancer.