Disruption of the NPM1 gene by translocation or heterozygous deletion is found in human hematopoietic malignancies [171], such as acute promyelocytic leukemia (APL), anaplastic large cell lymphoma (ALCL), and in premalignant myelodysplastic syndromes (MDS), reviewed in [31, 171]. Here, NPM1 is linked to acute promyelocytic leukemia.