 The TEL-AML1 fusion in precursor-B ALL is generated by a cryptic 12;21 translocation that is detectable by fluorescence in situ hybridization (FISH).     ///    Utilizing FISH to distinguish subgroups of TEL-AML1 fusion patients may have important prognostic implications.     ///    The aim of the study was to determine whether additional copies of TEL-AML1 have clinical significance.     ///    A larger and longer-term follow-up study will be required to verify the possible clinical significance of the presence of multiple TEL-AML1 fusions..     ///    "Eight patients (7 males/1 female, mean age 46 months) with two or more TEL-AML1 fusion signals and 24 with single TEL-AML1 fusion signals (18 males/6 females, mean age 52 months) were identified. "