CD200 and chronic myelogenous leukemia, BCR-ABL1 positive: Skorski's group identified electron leakage from mitochondrial respiratory chain complex III (MRC-cIII) as a major source of ROS mediated DNA damage in CML LSC and targeted its activity with an inhibitor of Rac2, a GTPase that can modify mitochondrial membrane potential and electron flow through MRC [12].