Cytogenetic pattern of childhood leukemia in Taiwan

Background: Cytogenetic analyses of leukemic cells can be used to define sp ecific subgroups of leukemia with different prognoses and, thereby, indicat e appropriate treatment for individual cases. In this study, we investigate d the cytogenetic pattern of childhood leukemia in Taiwanese patients. Methods: A modified trypsin method of Seabright was used for G-banding of m etaphase cells. Results: From October 1996 to January 1999, 111 children with a diagnosis o f leukemia were enrolled in the study. Of these, 73 patients had a diagnosi s of acute lymphoblastic leukemia (ALL) and 63 of these patients had succes sful karyotyping of their leukemic cells. Among them, 20 (30.3%) had a norm al karyotype, five had hypodiploidy (all had 45 chromosomes), five had low hyperdiploidy (47-50 chromosomes), 16 (24.2%) had high hyperdiploidy (> 50 chromosomes), and 20 had pseudodiploidy. Chromosomal, translocation was ide ntified in 24 (36.4%) of the ALL patients, 17 of whom had recurrent translo cations including 10 with CD10(+) B-precursor ALL [4 with t(9;22), 5 with t (1;19), and 1 infant with t(8;14)(q24;q11)], one neonate with CD10(-) early pre-B ALL with t(4;11), three B-cell cases with t(8;14), and three T-cell cases [2 with t(11;19) (q23;p13), and 1 (11;14)(p13;q11)]. One B-precursor patient had dic(9;12). Karyotypes of the 30 patients with acute myeloid leu kemia (AML) included eight with t(8;21); seven with the French-American-Bri tish-M2 subtype (FAB-M2) and one with M1. All four of the patients with M3 had t(15;17), one patient with M4 had inv(16) and 7q-, one with M4Eo (M4 wi th eosinophilia) had t(7;16) (q21;q22), one with MO had t(4;11) (q21;q23), and the remaining II had a normal karyotype. Three of the five adult-type c hronic myeloid leukemia patients had standard Philadelphia chromosome, and the other two had a variant-form of Philadelphia chromosome. Both of the pa tients with juvenile myelomonocytic leukemia and one patient with myelodysp lastic syndrome had a normal karyotype. Conclusions: Most findings were similar to previous reports. Although the h igh proportion of FAB-M2 patients (7/8) with t(8;21) and the consequently h igher frequency (26.7%) of this translocation in the 30 AML cases in this s tudy might have significance, a larger series of cases is needed to establi sh this finding.