The MDR (Multidrug-Resistance) Genes are implicated on the resistance of several types of cancer. The most important on leukemia are the ABCB1 and ABCG2- ABCB1 are implicated on resistance and severity on Acute Myeloid Leukemia and pediatric Acute Lymphoblastic Leukemia. Those transporters use ATP for use. Metformin decrease the intracellular ATP (Adenosine triphosphate) reserve the by the activation of AMPK. Recently on MCF7-Adr (Michigan Cancer Foundation 7, breast cancer cell line) cancer cell line, Metformin block the function of the P-glycoprotein by the inhibition of the Nuclear Factor -kappa-B.