The Role of p53 in Megakaryocyte Differentiation and the Megakaryocytic Leukemias of Down Syndrome

Sequence analysis of the p53 tumor suppressor gene was performed on diagnostic blood and bone marrow samples from nine children with Down syndrome and acute megakaryoblastic leukemia. p53 sequence alterations were not observed in any of seven cases of transient leukemia; however, samples from two of three patients with acute megakaryoblastic leukemia harbored sequence alterations. The acquisition of both mutations (Gly245Val and Arg72Pro) in the transformation from transient leukemia to overt acute megakaryoblastic leukemia suggests a functional role of mutant p53 in the evolution of this disease.