Cytogenetic analysis in childhood acute lymphoblastic leukemia: experience at a single institution in Korea.

We evaluated major cytogenetic abnormalities associated with childhood acute lymphoblastic leukemia (ALL) through both fluorescent in situ hybridization and conventional chromosomal analysis for 132 ALL patients diagnosed at St Mary's Hospital in Korea. Chromosome abnormalities have been detected in 92% of patients. Eighteen (14%) patients showed numerical abnormalities only, 50 (38%) patients showed structural abnormalities only, and 53 (40%) patients showed both. The simultaneous trisomies 4, 10 and 17 were observed in 23 (17%) patients. Of the patients with abnormal karyotypes, recurrent structural abnormalities were determined in 103 (78%) cases. t(12;21)(q13;q22) was found in 29 (22%) out of 132 patients, 9p abnormalities in 13 (10%) patients, t(1;19)(q23;p13.3) in 11 (8%) patients, t(9;22)(q34;q11.2) in 11 (8%) patients, and 11q23 abnormalities in 7 (5%) patients. Interestingly, we identified five uncommon translocations such as t(5;12) (q33;p13), t(14;19)(q32;q13.1), t(12;16)(p13;q13), der(1)t(1;12)(p32;p13), and t(5;15)(p15;q11.2). Our study pool is representative of pediatric ALL patients in Korea as it consists of about 20% of patients diagnosed annually in Korea. We believe that the data provided will aid in comparative studies of the treatment outcomes, as well as the type and incidence of chromosomal abnormalities associated with childhood ALL in various Asian nations and Western countries.