Abnormalities of chromosome bands 13q12 to 13q14 in childhood acute lymphoblastic leukemia

Purpose: Little is known about nonrandom deletions of chromosome bands 13q1 2 to 13q14 (13q12-14) in acute lymphoblastic leukemia (ALL), We determined the prognostic significance of cytogenetically identified breakpoints in 13 q12-14 in children with newly diagnosed ALL treated on Children's Cancer Gr oup protocols from 1988 to 1995. Patients and Methods: Breakpoint in 13q12-14 were identified in 36 (2%) of the 1,946 cases with accepted cytogenetic data. Outcome analysis used stand ard life-table methods. Results: Seventeen patients (47%) with an abnormal 13q12-14 were classified , according to the National Cancer Institute (NCI), as poor risk, and 15 pa tients (42%) were standard risk; four(11%)were infants less than 12 months of age. Eight cases had balanced rearrangements of 13q12-14, 27 patients ha d a partial loss of 13q, and one held both ct partial gain and a partial lo ss. The most frequent additional abnormalities among these patients were an abnormal 12p, a del(bq), a del(9p), a 14q11 breakpoint, and an 11q23 break point. Nineteen patients were pseudodiploid, 10 were hyperdiploid, and seve n were hypodiploid. Patients with an abnormal 13q12-14 had significantly wo rse event-free survival than patients lacking such an abnormality, with est imates at 6 years of 61% (SD = 14%) and 74% (SD = 1%), respectively (P =.04 ; relative risk = 1.74), Overall survival, however, was similar for the two groups (P =.25). The prognostic effect of an abnormal 13q was attenuated i n a multivariate analysis adjusted for NCI risk status and ploidy IP =.72), Conclusion: Aberrations of 13q12-14 may contribute to leukemogenesis of chi ldhood ALL and confer increased risk of treatment failure but are associate d with other poor-risk features. (C) 2000 by American Society of Clinical O ncology.