Do terminal deletions of 11q23 exist? Identification of undetected translocations with fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) was performed on bone marrow or peripheral blood cells thought to contain a del(11)(q23q25) from four patients who had acute leukemia or myelodysplasia. Cells from all patients were shown to contain translocations that involved chromosome 6 in three of them. Our data suggest that a large proportion of presumptive del(11)(q23) or del(11)(q23q25) chromosomes may represent previously unidentified translocations that can be detected by FISH.