In addition, we recently found that hypermethylation of PTEN is associated with downregulation of PTEN transcription in imatinib-resistant leukemia cells isolated from individuals with chronic eosinophilic leukemia, chronic myeloid leukemia (CML), and Philadelphia positive acute lymphoblastic leukemia (Ph+ ALL) [20]. This evidence concerns the gene PTEN and chronic myelogenous leukemia, BCR-ABL1 positive.