NPM1 and acute myeloid leukemia: Since the time a 4-nucleotide insertion in NPM1 gene and its significance in AML was discovered by Falini et al. in 2005 [52], much attention was paid to unveiling the mechanism of AML triggered by NPM1 mutation. NPM1 encodes a multifunctional protein, involved in ribosome biosynthesis and transport, DNA replication and repair, chromatin remodeling, protein chaperoning, regulation of cell cycle, embryogenesis and oncogenesis [131, 132].