However, despite the advancement of breast cancer therapeutics, including anti-hormonal therapy tamoxifen, tyrosine kinase inhibitors and the recent development of novel selective estrogen receptor degraders (SERDs), cell cycle CDK4/6 inhibitors, PARP-inhibitors, immunotherapy, antibody–drug conjugates (ADCs) and inhibitors of the PI3K/protein kinase B(AKT)/mammalian target of rapamycin (mTOR), none of these approaches are differentiation-based modalities [12–14]. The gene discussed is ESR1; the disease is breast cancer.