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Translocations involving the MLL gene on chromosome 11q23 are noted in a subset of acute myeloid leukemias (AML) as well as acute lymphoblastic leukemias/lymphomas (ALL). In addition, treatment-related leukemias (5-10% of all leukemias), particularly those following treatment with anti-topoisomerase II or intercolating topoisomerase II inhibitors, but even those after more conventional alkylating or radiotherapy, often have translocations involving 11q23. The detection of translocations involving MLL is important in the diagnosis of patients with AML and ALL as they predict a poor overall prognosis. On the molecular level, the MLL gene on 11q23 is often juxtaposed with a variety of partner genes; the most frequent are listed below, although variant translocations involving other partners have been widely described in the literature. t(4;11)(q23;q23): Represents ~1/3 of cases and found mainly (95%) in precursor B acute lymphoblastic leukemia/lymphoma (CD19+ in 75%, CD10+ in 15%) as well as treatment-related ALL (5%). Children represent ~1/2 of cases with infants <1 year of age accounting for 1/3 of all cases. The gene involved on 4q21 is AF4, a transcription activator. t(6;11)(q27;q23): Represents 5% of cases, mostly in children and young adults, with a male predominance. The gene involved on 6q27 is AF6, which plays a role in signal transduction. t(9;11)(p23;q23): Represents 25% of cases and found mainly in AML, of which 70% show M5A morphology and 10% show M4, but 10% of cases represent ALL. In both de novo and therapy-related ALL, children represent half of cases (infants <1 year accounting for 15% of all cases). The gene involved in 9p22 is AF9, a transcription activator. t(10;11)(p12;q23): Represents 5% of cases, most of which present with M4 and M5 morphology. The gene involved on 10p12 is AF10, a transcription activator. t(11;19)(q23;p13.1): Represents 5% of cases, most of which present with AML M4 or M5 morphology. The gene involved on 19p13.3 is ELL, a transcription activator. t(11;19)(q23;p13.3): Represents 5% of cases. Acute lymphoblastic leukemia, biphenotypic acute leukemias and AML M4, M5. Mostly found in infants (roughly 50% of cases) and other children or young adults. The gene involved in 19p13.3 is ENL, a transcription activator. Probe type: Dual color breakapart
Organ: Blood/Bone Marrow
Disease State: Precursor B-Lymphoblastic Lymphoma/Leukemia (B-ALL)
CPT Code(s): 88374 (reference only; CPTs may vary)
Turnaround Time: Within 4-6 business days of receipt
Schedule: Monday - Friday
• Peripheral blood, Preferred: 3 ml in sodium heparin (green top) / Acceptable: 3 ml in EDTA (purple top) - OR - • Bone marrow aspirate, Preferred: 1-2 ml in sodium heparin (green top) / Acceptable: 1-2 ml in EDTA (purple top) - OR - • Fresh tissue in RPMI