Nonrandom chromosomal abnormalities in acute lymphoblastic leukemia of childhood.

The leukemic cell karyotype was studied in 103 children with acute lymphoblastic leukemia. An abnormal chromosome pattern was revealed in 81 of 98 patients studied before treatment (82.6%) and in the five children studied in relapse. Aside from specific chromosomal abnormalities defined by the Third International Workshop on Chromosomes in Leukemia, other nonrandom rearrangements were observed, particularly del(14)(q11-13), del(12)(p11-12), and t(1;19)(q22-23;p13), often associated with partial trisomy for 1q. Patients with del(14) had tumorous lymph-nodes or other extramedullary tumors. The course of the disease in these children was rapid. Patients with markers such as Ph, 6q-,14q+, and with a t(4;11) had a low incidence of complete remission and short survival. The most favorable course of the disease was observed in the group of children with over 50 chromosomes in the leukemic cells.