Publication Date:
2011-11-18
Description:
Abstract 565FN2 Hyperdiploidy 〉50 chromosomes (HD〉50) has long been recognized as favorable group in childhood B-ALL but there is still debate on the factors contributing to heterogeneity of prognosis observed within this entity. Better outcome has been reported for patients (pts) presenting DNA index (DI) 〉1.16 (Blood 1985;10:213), ≥56 chromosomes (Leukemia 1996;10:213), triple trisomies (TT) +4,+10,+17, double trisomies +4,+10 (Leukemia 2005;19:734) and trisomy 18 (Blood 2003;102:2756) but there is no consensus between the reports and these factors are differently applied in current protocols. We studied these factors in the pts with HD〉50 enrolled in the ALL 58951 trial, BFM related. HD〉50 were detected by cytogenetics (karyotype/FISH) and/or flow cytometry (DI). In order to analyze the outcome of HD〉50 itself, pts with recurrent unfavorable translocations t(9;22), 11q23/MLL+, with t(1;19), t(12;21) or Down Syndrome were excluded, as well as near-triploidies/duplication of hypodiploidies 30–39 chromosomes. Pts were stratified into 4 risk groups (VLR/AR1/AR2/VHR) according to DI, Modal Number of Chromosomes (MNC), WBC, CNS/gonadal involvement, presence of VHR features (unfavorable translocations, poor response to prephase, residual disease (MRD) at the end of induction 〉10-2). VLR was defined as: DI〉1.16 or MNC〉50, WBC50. Median age was 3 years and median WBC was 5.6×109/L. After prephase, 3% (N=17) were poor responders; initial risk group distribution into VLR/AR1/AR2/VHR was 45%/47%/5%/3%. After induction, 540 (99.8%) reached complete remission, 455 of whom had an MRD evaluation: MRD50, those with ≥58 chromosomes, stand every chance of being cured. Our results stress the necessity of karyotype for identifying them since this is the only way to assess MNC. They can also be detected (less accurately) by DI (DI ≥1.24). Therefore, both MNC and DI should be used for stratifying pts in the very low risk groups. Disclosures: No relevant conflicts of interest to declare.
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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