Fig. 1. Suggested models of AML transformation. Three suggested scenarios of step by step transformation in human AML, leading from a normal cell (orange) to a premalignant cell (pink) and, finally, to a malignant cell (brown) with clonal expansion: Scenario 1; both the initial transforming incident and following mutations leading to clonal expansion occur at the level of multipotent precursors; Scenario 2; the initial transforming incident occurs at the level of multipotent precursors, whiles the cooperating mutational event leading to clonal expansion occurs at the level of committed myeloid progenitors; and Scenario 3; both initial and following mutations occur at the level of committed myeloid precursors [2].