In this work, using MDR (overexpressing ABCB1) and non-MDR cell lines (Lucena and K562, respectively) as models of CML, we demonstrated through EMSA and ChIP analyses that β-catenin binds to the TCF/LEF consensus binding site in the ABCB1 promoter. The gene discussed is HNF4A; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.