MLL t(11q23)

F MLL

Associations:

Acute Myelogenous Leukemia, Acute Lymphoblastic Leukemia

CPT Code:

88367 x2 - Morphometric analysis

Turnaround Time:

3 days

Methodology:

Fluorescence in situ hybridization (FISH)

Specimen Requirements:

5.0ml (min. 3.0 ml) peripheral blood in sodium heparin preferred, EDTA accepted

3.0ml (min 1.0ml) bone marrow in sodium heparin preferred, EDTA accepted

5mm3 fresh tissue in MPLN RPMI media

3.0ml (min 2.0ml) FNA in MPLN RPMI  media

Causes for Rejection:

Clotted specimen; specimen exposed to extreme temperature; anticoagulant toxic to cells; insufficient number of cells

Specimen Stability:

Peripheral blood and bone marrow stable at 18-25°C for 72 hours

Fresh tissue or FNA at 2°-8°C stable for 72 hours

Storage and Handling:

Whole blood and bone marrow ship ambient; fresh tissue or FNA ship in a styrofoam container with an ice pack (do not allow ice pack to directly contact sample)

Reference Range:

FISH analysis detects the presence or absence of a translocation disrupting MLL

Indication:

Both acute myelogenous leukemia (AML) and acute lymphoblastic leukemia (ALL) have translocations associated with disruptions in the MLL gene. Rearrangements of the MLL gene have been reported in 5-10% of acute leukemias. Among ALL patients less than one (1) year of age, approximately 60-80% have a chromosome aberration involving an 11q23 alteration. In children with ALL older than one (1) year, the incidence of MLL rearrangements is less than 10%.  These alterations are even more common in secondary leukemias occurring in patients treated with chemotherapeutic agents that are topoisomerase II inhibitors (approximately 85% of the cases). The most common rearrangements involving 11q23 abnormalities are t(4;11)(q21;q23), t(9;11)(p22;q23), and t(11;19)(q23;p13).

References:

1. Cox et al. (2004). Chromosomal aberrations of the 11q23 locus in acute leukemia and frequency of MLL gene translocation: results in 378 adults patients. Am J Clin Pathol 122(2):298