Breast neoplasms can be divided into Luminal A (ER and/or PR+ HER2− and 58.5% prevalence), Luminal B (ER and/or PR+ HER2− or HER2+ and 14% prevalence), HER2− enriched (ER and/or PR− HER2+ and 11.5% prevalence), and Triple Negative (ER−, PR− and HER2− and 16% prevalence) [12]. The gene discussed is ESR1; the disease is breast neoplasm.