الفهرس 
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Abstract
Acute myeloid leukemia (AML) is a hetereogeneous group of hematologic maliganacy. Despite that recurrent chromosomal abnormalities are present in a significant proportion of AML patients, leukemia cells from 40% to 50% of the patients have a normal karyotype and lack a reliable biological marker, thus making difficult the investigation of the etiologies and monitoring of residual disease in some of the de novo AML patients (Chou et al., 2006)
Attempts to stratify AML-normal karyotype (AML-NK) using gene microarrays succeeded in associating gene – expression patterns with differences in response to treatment , but no specific genetic subgroups emerged (Bullinger et al., 2004). Molecular analyses of AML-NK identified several mutations that target genes encoding for transcription factors (AML1 and CEBPA: 2% - 3% and 15%-20% of cases, respectively), receptor tyrosine kinases (FLT3 and KIT: 25%-30% and 1%, respectively), (Schnittger et al., 2002 and Beghini et al., 2004) and the RAS genes (105) Kiyoi et al., 1999), as well as a partial tandem duplication of MLL gene (MLL-PTD 5%-10%) (’Schnittger et al., 2000 and Steudel et al., 2003).
Falini et al. (2005) discovered that nucleophosmin (NPM1) gene mutations target 50% to 60% of adult AML-NK. This is the most common genetic lesion described to date in adult de novo AML (about one third of patients). Since NPM1 Mutations dislocate nucleophosmin into cytoplasm, they named this subgroup NPM-cytoplasmic positive (NPMc+) AML.
Due to their frequency and stability, NPM1 mutations may become a new tool for monitoring minimal residual disease in AML-NK. Future studies should focus on clarifying how NPM mutants promote leukemia, intergrating NPMc+ AML in the upcoming World Health Organization leukemia classification, and eventually developing specific antileukemic drugs (Falini et al 2007).
Aim of the work
This study will review the recent reports about nucleophosmin gene and protein and the clinical importance of NPM mutations in patients with AML.