The CXXC5 gene is evolutionarily conserved, with a length of 35.5 kbp, and localized on human chromosome 5q31.2, where it is close to regions frequently deleted in patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) and found to be an abnormal fusion partner with MN1 [12–15]. Here, MN1 is linked to acute myeloid leukemia.