Last update:
02-Feb-2012

In recent years a number of gene mutations (Flt-3, NPM1, CEBPA, MLL, N-RAS, RUNX1, WT-1, IDH) and deregulated expression of genes (WT-1, EVI1, PRAME, BAALC, ERG, MN-1) have been identified, illustrating the enormous heterogeneity of cytogenetically defined subsets of acute myeloid leukemia (AML), in particular in the large subset of cytogenetically normal (CN) AML. Monitoring of the minimal residual disease (MRD) in AML patients is now recognized to be an important diagnostic tool that can be used to assess the response to treatment and to establish the risk of relapse in the individual patient. The most recent techniques, based principally on immunophenotyping by multiparametric flow cytometry (MFC) or real time-quantitative polymerase chain reaction (RQ-PCR) analysis, have in most instances the sensitivity to detect at least one leukemic cell out of 10⁴ background cells. Standardized RQ-PCR procedures for the most common types of fusion transcripts present in AML (i.e., PML/RARα, AML1/ETO and CBFB/MYH11, representing about 30% of all AML cases) have now been developed, permitting large scale MRD studies. In addition, a reliable and highly sensitive RQ-PCR test can be performed in almost 90% of patients with NPM1 mutations (about 35−40% of all AML cases). Finally, RQ-PCR assessment of the disease level is, through the use of WT-1 overexpression, now feasible in more than 70% of AML patients.

Key words: Acute myeloid leukemia (AML), Minimal residual disease (MRD), NPM1, RQ-PCR, WT-1.