[Cytogenetic characteristics of 163 children with acute lymphoblastic leukemia]

To further understand the cytogenetic characteristics of pediatric acute lymphoblastic leukemia (ALL).

Cytogenetic abnormalities of 163 children with newly diagnosed ALL (0-17 years of age) were evaluated by conventional cytogenetic analysis and fluorescent in situ hybridization findings.

Chromosome abnormalities were detected in 87.7% of patients (143/163). The ploidy levels most frequently observed among ALL patients were high hyperdiploidy (51-67 chromosomes) (45 cases, 27.6%), Chromosomes X and 21 were gained in 100% of these cases. The most common genetic alterations were t(12;21)/ETV6/RUNX1 (26 cases, 16.0%), followed by t(1;19)/TCF3/PBX1 (13 patients, 8.0%), t(4;11)/MLL rearrangement and t(8;14) IGH/MYC (6 cases, 3.7%), t(9;22)/BCR/ABL(2 cases, 1.2%), and iAMP21 (1 patient, 0.6%). The no-classical structural abnormalities included dup(1q) in 20.2%, del(6q) and del(9p) in 10.4%, del(12p) in 12.9% and del(13q) in 5.5%. The incidences of t(12;21), t(1;19), t(9;22) and high hyperdiploidy were consistent with reports in Western children (P>0.25). The incidence of (9;22) seemed to be much lower in our study than that in Korea (1.5% vs 9.5%, P<0.005).

Cytogenetic findings of childhood ALL patients are similar to that of Western countries, it seems no more adverse risk factors.