RESUMEN
Between 1987 and 1990 cytogenetic studies of bone marrow and lymphocytes from peripheral blood from 25 patients with de novo ALL were performed. All cases had chromosomal aberrations; however in 23 patients a normal cell line was also present. The most important structural aberrations found were: t(17;19)(q11;p13), t(2;9;22)(q34;q34;11), t(1;7)(p13;q33), t(6;11)(q26;p16), t(3;4)(q24-25;q26), t(1;12)(q23;q34), t(2;18)(q15;p12), t(2;4)(q23;q35) and t(4;11)(q21;q23). These chromosome abnormalities correlate with the response to treatment and survival and improve the identification of high-risk patients. Our study shows the presence of some chromosomal abnormalities different to those reported in the literature; however the breakpoints involved seem to be the same which suggests that these critical regions may be directly involved in the pathogenesis of these disorders.