Molecular Characterization of 34 Children with Acute Leukemia and MLL gene Rearrangements in Argentina

Author(s): Adrian P. Mansini, Claus Meyer, Marta Gallego, Patricia L. Rubio, Adriana Medina, Mariela Coccé, Jorge Rossi, Pedro Zubizarreta, Rolf Marschalek, Maria Sara Felice, Cristina N. Alonso

Translocations involving the Mixed Lineage Leukemia (MLL) gene can be detected in de novo acute lymphoblastic leukemia (ALL), acute myeloblastic leukemia (AML), therapy-related acute leukemias, and are highly associated with infant acute leukemia. Analysis of these genetic rearrangements is required for stratifying patients into risk groups for treatment tailoring in current protocols. Their occurrence usually predicts a poor outcome. We report the biological and molecular characteristics of 34 pediatric acute leukemia cases with MLL rearrangements. Samples were further analyzed by LDI-PCR to characterize the respective fusion partner genes. AFF1 was the main partner gene in ALL, while MLLT10 was predominantly identified in AML in this series. Although RT-PCR allowed quick detection of most cases with MLL gene rearrangements, the routinely performed cytogenetic analysis combined with LDI-PCR was a powerful tool for accurate diagnosis and subsequent tailoring of treatment.