Myeloid/Lymphoid Or Mixed Lineage Leukemia (MLL)

MLL is a frequent target for recurrent translocations in acute leukemias that may be characterized as acute myeloid leukemia (AML), acute lymphoblastic leukemia (ALL), or mixed lineage (biphenotypic) leukemia (MLL). Leukemias with translocations involving MLL possess unique clinical and biologic characteristics and are often associated with poor prognosis. MLL rearrangements are found in more than 70% of infant leukemias, whether the immunophenotype is more consistent with ALL or AML6, but are less frequent in leukemias from older children. MLL translocations are also found in approximately 10% of AMLs in adults, as well as in therapy-related leukemias, most often characterized as AML, that develop in patients previously treated with topoisomerase II inhibitors for other malignancies.