Genetic abnormalities in acute myelogenous leukemia with normal cytogenetics.

Acute myelogenous leukemia (AML) results from a differentiation block of hematopoietic progenitor cells along with uncontrolled proliferation. The cytogenetic abnormality at initial diagnosis is the single most important prognostic factor classifying AML patients into three prognostic categories: favorable, intermediate, and poor risk. Currently, favorable-risk AML patients are usually treated with contemporary chemotherapy, and poor-risk AML patients receive allogeneic stem cell transplantation if suitable stem cell donors exist. The approximately 40% of AML patients without identifiable cytogenetic abnormalities (NC AML) are classified as intermediate risk. The optimal therapeutic strategies for these patients are largely unclear. Emerging data recently suggested that molecular study of the mutations of NPM1, FLT3, MLL, and CEBPalpha and alterations in expression levels of BAALC, MN1, and ERG may identify poor-risk patients with NC AML. Further prospective studies are needed to confirm whether NC AML patients with poor risk have improved clinical outcomes after more aggressive therapy.