More recently, we demonstrated that in PTPRG‐negative CML cell lines, the methylating enzyme DNA (cytosine‐5)‐methyl transferees 1 (DNMT1) is over‐expressed, bind to PTPRG promoter and is responsible for its hypermethylation, while its inhibition or downregulation correlates with PTPRG re‐expression (Tomasello et al., 2020). This evidence concerns the gene DNMT1 and chronic myelogenous leukemia, BCR-ABL1 positive.