ESR1 and breast cancer: The aims of this study are: (1) to evaluate the expression of Topoisomerase II Alpha in Invasive mammary carcinoma, (2) to evaluate the utility of Top 2 A as an independent prognostic marker, and (3) immunohistochemical (IHC) expression of Top 2 A in breast cancer and its correlation with the tumour type, size, pathologic stage, grade and estrogen receptor (ER)/progesterone receptor (PR) and HER2/neu status.