Although dysregulations in epigenetic modulators such as histone methyltrasnferases have already been described for some hematologic malignancies, to date very limited data is available for CML, especially when considering the lysine methyltransferase MLL2/KMT2D and MLL3/KMT2C. The gene discussed is KMT2D; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.