Cytogenetics in acute lymphoblastic leukemia in Mexican children: An institutional experience

Background Cytogenetic studies in acute lymphoblastic leukemia (ALL) have i dentified numerical and structural chromosomal abnormalities related to the disease's pathophysiologic characteristics. These findings correlate with prognosis and response to treatment in ALL patients. The purpose of this st udy was to define the frequency of chromosomal abnormalities in a group of Mexican children with ALL and to compare these data with those reported in the literature. Methods. Bone marrow chromosome studies with GTG bands were performed in 15 0 pediatric patients with ALL who were naive to antileukemic treatment and aged from 5 months to 16 years; the majority was diagnosed as L1. Results. Among 131 patients, 30 (22.9%) karyotypes were normal and the rema ining 101 (77.1%) had abnormal karyotypes with numerical and/or structural abnormalities. Among patients with numerical abnormalities, the most freque nt karyotypes were hyperdiploidy with 51-65 chromosomes (30 patients) and h yperdiploidy with 47-50 chromosomes (18 patients). Among recurrent, non-ran dom, and primary structural abnormalities, the most frequent was t(9;22), f ollowed by t(1;19). Aberrations involving band 11q23 were net: detected, an d only one of two patients with L3 had the t(8;14). Of the secondary non-ra ndom abnormalities, dup(lq), del(6q), and i(7)(q10) were found. Conclusions. The frequency and type of chromosomal abnormalities found was comparable to those reported in the literature with similar methodology and pediatric populations; however, the number of cases analyzed should be inc reased to create a database of Mexican children with ALL, and several patie nts require molecular analysis to identify chromosomal abnormalities not de tected through conventional cytogenetic studies. (C) 2001 IMSS. Published b y Elsevier Science Inc.