Nevertheless, these studies have contributed their experimental results to classify tumors into different types based on the lymph node status, tumor grade, molecular type, and the presence of predictive markers such as estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor (HER2) (Perou et al., 1999; Holliday and Speirs, 2011). This evidence concerns the gene ESR1 and neoplasm.