BONE-MARROW KARYOTYPES OF CHILDREN WITH NONLYMPHOCYTIC LEUKEMIA

Bone marrow (BM) karyotypes from 16 consecutive children presenting with nonlymphocytic leukemia were established with the use of banding techniques, before therapy. The 2 patients with chronic myeloid leukemia (CML) showed the Philadelphia (Ph1) translocation (9q+;22q-). Five of the 14 patients with an acute nonlymphocytic leukemia (ANLL) presented no acquired cytogenetic abnormalities, but 1 of these 5 showed a high level of hypodiploidy. One patient with AML evidenced a variant of the Ph1 chromosome originated as a translocation (12p+;22q-). Nonrandom abnormalties (-7; 7q-; +8; t(8;21); -21) were found in 6 patients, isolated or in association with other aberrations. Among the random abnormalties, apparently balanced translocations and chromosomal deletions were observed. In ANLL, no correlation was found between morphologic diagnosis and cytogenetic findings. The presence of BM cells with a normal karyotype at diagnosis was associated with an improved remission rate and survival time. Followup studies were performed in 4 ANLL patients with an abnormal cell clone at diagnosis. Three of them achieved hematologic remission; their BM karyotype was normal at that stage. In the 4th patient, generalization of the abnormal karyotype in BM cells was seen in the terminal phase of the disease. Chromosome identification techniques have greatly improved knowledge of acquired BM aneuploidy found in leukemia. Nonrandom patterns of abnormalities have been found. Analyses of larger series of patients using advanced banding techniques and systematic followup studies will ascertain the significance of these cytogenetic abnormalities for diagnosis, prognosis, and neoplastic transformation.