The NPM1 mutations occur in exon 12 and the most common of these mutations, type A, are as result of a tetra-nucleotide insertion (TCTG) at position 956-959 of NPM1 gene that observe in approximately 80% of cases NPMc+ AML. 1,6  Molecular markers are useful in dissection of this heterogeneous group of AML patients into prognostically different subgroups.   7  This mutation is specific for malignant clone and potentially is a good marker of MRD.   7. Here, NPM1 is linked to acute myeloid leukemia.