 TEL/AML1-positive childhood acute lymphoblastic leukemias (ALLs) generally have low-risk features, but still about 20% of patients relapse.     ///    "Our initial molecular genetic analyses in 2 off-treatment relapses suggested that the initial and relapse clones represent different subclones that evolved from a common TEL/AML1-positive, treatment-resistant precursor. "    ///    "In order to further elaborate on this hypothesis, we studied 2 patients with late systemic relapses of their TEL/AML1-positive ALL (41 months and 49 months after initial diagnosis, respectively) who had distinct clonal antigen receptor gene rearrangements at diagnosis and relapse. "    ///    The matching genomic TEL/AML1 breakpoints of the initial and the relapse clones in these patients confirmed their origin from a common progenitor cell. 