Loss of heterozygosity at D3S2 locus of short arm of chromosome 3 in chronic myelogenous leukemia.

Loss of heterozygosity (LOH) on the short arm of chromosome 3 was studied in four patients with chronic myelogenous leukemia (CML). The bcr gene rearrangement-negative spleen cells and a B-cell line were used as normal tissue controls. Five probes showing restriction fragment length polymorphisms (RFLP) and a variable number of tandem repeats on chromosome 3 were used. DNA patterns in Southern blotting were compared between normal cells and leukemic cells. One of the four patients had LOH at the D3S2 locus mapped to 3p14.3-3p21.3. The LOH was detected in the blastic phase, but not in the chronic phase. This patient showed normal chromosomes 3 in the blastic phase. These data suggest the possibility of the existence of LOH in CML, occurring as a secondary event in the blastic phase, and which might have been induced by submicroscopic deletion or somatic recombination.