APOBEC3A and APOBEC3B have been linked to persistent cell evolution and therapy resistance in lung cancers [41,43,44], and APOBEC3B has been linked to resistance against androgen receptor (AR)-targeted therapy and Tamoxifen in prostate and estrogen receptor-positive (ER+) breast cancers [40,53]. The gene discussed is ESR1; the disease is breast carcinoma.