A NONRANDOM CHROMOSOME ABNORMALITY FOUND IN PRECURSOR-B LINEAGE ACUTELYMPHOBLASTIC-LEUKEMIA - DIC(9-20)(P13-Q11)

A comparison of cytogenetical data on acute lymphoblastic leukaemia st udied at four large European centres has revealed a non-random dicentr ic chromosome abnormality: dic(9;20) (p1?3;q11) in 10 patients, nine o f whom were children. All had early precursor-B lineage ALL, and eight children had a nonstandard risk clinical presentation. The origin of the dicentric chromosome was demonstrated using a range of chromosome handing techniques. This was confirmed by FISH using paints and centro meric probes for chromosomes 9 and 20, together with a number of cosmi d probes. The follow-up time of these patients is presently too short and the number of patients too few to determine the prognostic signifi cant of this chromosome abnormality.