Progression from myelodysplastic syndrome with monosomy 7 to acute monoblastic leukemia with MLL gene rearrangement

We report a case of myelodysplastic syndrome (MDS) with the 11q23 translocation at its leukemic transformation. Southern blot analysis demonstrated that the MLL gene on chromosome 11 was rearranged during the progression from MDS to acute leukemia. The clinical observation in this case supports the notion that leukemic transformation involves multiple cytogenetic evolutionary progresses, and that MLL gene rearrangement corresponds to the final step of leukemogenesis.