The chromosomal alterations at 11q23 that involve the mixed-lineage leukemia gene (MLL, HTRX1, HRX, ALL1) are one of the most common cytogenetic abnormalities in acute leukemia and have been associated with a poor prognosis.
The partial tandem duplication of the ALL1 (MLL) gene is found in patients with AML and trisomy 11 as a sole cytogenetic abnormality and in 11% of patients with AML and normal cytogenetics.
11q23 translocations (t(11q23)) are recurring cytogenetic abnormalities in both acute myeloid leukemia (AML) and acute lymphoblastic leukemia, involving the same gene, ALL1 (or MLL).
We conclude that molecular rearrangement of ALL-1 often can be detected in de novo AML, despite the absence of cytogenetic abnormalities involving 11q23.