The TEL/AML1 fusion gene was located on the derivative chromosome 21 but a segment of the long arm of a chromosome 3 was inserted between the proximal part of the short arm of the derivative chromosome 12 and the reciprocal part of the AML1 gene.     ///    Fluorescence in situ hybridization with TEL/AML1 probes and chromosome paints revealed complex rearrangements. 