Genetic alteration of epigenetic regulator genes such as Additional sex combs-like 1 (ASXL1), DNA (cytosine-5)-methyltransferase 3A (DNMT3A), runt-related transcription factor 1 (RUNX1), and Tet methylcytosine dioxygenase 2 (TET2) are frequently found in a CML blast crisis [81,82]. The gene discussed is TET2; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.