Clinical significance of cytogenetic findings at diagnosis and in remission in childhood and adult acute lymphoblastic leukemia: Experience from India

We report cytogenetic findings in 114 patients of acute lymphoblastic leuke mia (ALL), which includes 78 children (less than or equal to 15 years) and 36 adults (16-60 years). Chromosome aberrations;were detected in 109 (95%) cases. A lower frequency of hyperdiploidy (15%) in children and a higher fr equency of hypodiploidy both in children (38.4%) and adults (44.4%) were fo und, in contrast to literature. Translocations were detected in one third o f adult and pediatric cases. The incidence of t(9;22) was comparatively low in adults (7.7%). Frequency of t(1;19) was also low in overall ALL cases. Various other recurrent abnormalities such as del(6q), abn(11q23), i(9p), a bn(12p13), del(7q), and i(17q) were seen in our cases; a striking differenc e in the incidence of del(6q) (41%) and abn(11q23) (30%) was found in our s eries versus reported literature. Ploidy distribution indicated association of pseudo; and hypodiploidy with B-lineage, and hypodiploidy with T-lineag e in children-The occurrence of del(6q)) was more frequent in pediatric ALL with highly aberrant pattern and also with lymphadenopathy. Abn(11q23) was found to be early-B and pre-B specific. Kaplan-Meier analysis of overall s urvival revealed Prognostic value of sex, FAB, immunophenotype, and cytogen etic findings. Females and T-ALL patients had a better prognosis, whereas m ales and B-ALL patients had poor outcome in overall and pediatric age group s. Prognostic evaluation of cytogenetics indicated translocations as an ind ependent high-risk predictor in childhood (P < 0.008) and adult ALL (P < 0. 01). Childhood ALL with t(8;14) and t(4;11) and adults with t(9;22) had poo r survival. Cytogenetics of remission marrows demonstrated disappearance of abnormal clones in 31.4%, and expansion in normal clones in 50% of patient s. Persistence of original clones and development of new clones were observ ed in 20% and 33% of patients, respectively; whereas karyotype evolution wa s identified in 20% of patients. The prognostic significance of cytogenetic findings at diagnosis, and differential cytogenetic response in so-called clinical remission in our study indicated the utmost need for more intensiv e therapy for eradication of resistant clones, and necessity of sequential cytogenetic follow-up in these patients for identification of minimal resid ual disease. (C) Elsevier Science Inc., 1999. All rights reserved.