ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Given the high levels of Rac GTPases in CD34+ of CML patients and its importance as a key stimulator of ROS production [28] we decided to analyse by RT-Q-PCR the copy number of BCR/ABL-OOF transcript on CD34+ positive cells derived from the bone marrow of 7 CML patients.