KDM3B is a H3K9me1/me2-specific demethylase that was initially suspected of inhibiting the tumor activity of hematopoietic malignancies due to its location in the 5q31 chromosome region, which is a frequently deleted region in myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML) [16, 19–21]. The gene discussed is ME2; the disease is acute myeloid leukemia.