Segregation of the AML t(7;11)(p15;p15) translocation chromosomes in somatic cell hybrids

The t(7;11)(p15;p15) translocation is a recurrent chromosomal abnormality associated predominately with acute myeloid leukemia (AML) FAB M2 and occasionally with other types of AML or CML blast crisis. High resolution banding techniques have previously localized the breakpoints to 7q15.1 and 11p15.5. We have fused t(7;11)(p15;p15) blast cells from an AML patient to CHTG (hamster) cells in order to segregate the translocated chromosomes from their normal counterparts in somatic cell hybrids. Fusion events containing the derivative chromosomes or the normal chromosome 11 were enriched by panning with the antibodies M1C1 and MER2. These antibodies recognize cell surface markers which are expressed from genes which map to opposite sides of the breakpoint on chromosome 11 (11p13 and 11p15.5, respectively). Individual hybrids were expanded and typed with a series of ordered STSs from chromosomes 7 and 11, and hybrids containing the der(7) and der(11) chromosomes were identified. The segregation of the STSs between the two derivatives is in full agreement with the consensus breakpoint positions as determined cytogenetically. These hybrids may prove useful in further delineation of the breakpoint regions on chromosomes 7 and 11.