ELF5 is a transcription factor regulating key genes e.g., FOXA1, EGFR, and MYC, and has been described as potential regulator of anti-estrogen resistance in luminal breast cancer [41] and imatinib resistance in chronic myeloid leukemia [42]. The gene discussed is FOXA1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.