Cytogenetic Features of Infants Less Than 12 Months of Age at Diagnosis of Acute Lymphoblastic Leukemia: Impact of the 11q23 Breakpoint on

Cytogenetic analyses of pretreatment bone marrows were performed at local institutions as part of Childrens Cancer Group (CCG) protocol CCG-107 for infants less than 1 year of age with previously untreated acute lymphoblastic leukemia (ALL). Cytogenetic analyses from 39 patients (17 males and 22 females) were accepted after review. Several unique cytogenetic features were observed. Twelve patients (31%) had a t(4;ll)(q21;q23) and had a significantly shorter event-free survival (EFS) than did the other patients with adequate cytogenetic analyses (P = .009). Five additional patients had an 11q23 breakpoint, not associated with 4q21. When EFS for these 5 patients was compared with that of the t(4; 11) patients, even with these small numbers there was a strong, although not significant, suggestion that the t(4; 11) patients have a reduced EFS ( P = .09), indicating that the specific translocation, t(4;l l)(q21;q23), and not an 1 lq23 breakpoint per se, may be associated with the poor prognosis of these