Today, prognostication is based on clinical parameters such as lymph node status, tumor size, age and histological grade; complemented by estrogen receptor (ER), progesterone receptor (PgR) and epidermal growth factor receptor (EGFR/HER2) status [3]–[5], which combined separate subgroups with different clinical behavior, including Luminal A, B, HER2 and basal-like tumors [6], [7]. This evidence concerns the gene ESR1 and neoplasm.