Relapse of TEL-AML1–Positive Acute Lymphoblastic Leukemia in Childhood: A Matched-Pair Analysis

PURPOSE: The aim of this study was to investigate whether, in relapsed childhood acute lymphoblastic leukemia (ALL), the frequent genetic feature of TEL-AML1 fusion resulting from the cryptic chromosomal translocation t(12;21)(p13;q22) is an independent risk factor. PATIENTS AND METHODS: A matched-pair analysis was performed within a homogeneous group of children with first relapse of BCR-ABL–negative B-cell precursor (BPC) ALL treated according to relapse trials ALL-Rezidiv (REZ) of the Berlin-Frankfurt-Munster Study Group. A total of 249 patients were eligible for this study: 53 (21%) were positive for TEL-AML1, and 196 (79%) were negative. Positive patients were matched for established most-significant prognostic determinants at relapse, time point, and site of relapse, as well as age and peripheral blast cell count at relapse. RESULTS: Fifty pairs matching the aforementioned criteria could be determined. The probabilities with SE of event-free survival and survival at 5 years for matched TEL-AML1 posi...