In breast cancer, estrogen receptor (ER), progesterone receptor (PR), and Erb-b2 receptor tyrosine kinase 2 (ERBB2, previously named Human Epidermal Growth Factor 2 or HER2 or HER-2/neu2) are biomarkers known to be related to tumor growth and prognosis, and assessing their expression is necessary to define therapeutic management (3–7). This evidence concerns the gene PGR and breast cancer.