COP1 and acute myeloid leukemia: MLF2 belongs to the myeloid leukemia factor family, which is involved in myelodysplastic syndrome and acute myeloid leukemia.[43, 44] MLF2 and its homolog MLF1 share nearly 40% identity and are highly conserved in metazoans and mammals.[44, 45] Unlike the destabilizing effect of MLF2 on p53, it has been previously reported that MLF1 stabilizes p53 by suppressing constitutive photomorphogenic 1 (COP1) via COP9 signalosome subunit 3.[46] Therefore, it would be interesting to investigate the mechanisms underlying the opposite effects of MLF1 and MLF2 on p53 expression in the future.