Because of the uncommon morphology of blasts for AML with t(8;21), and absence of AML1-ETO fusion in the RT-PCR analysis, fluorescence in situ hybridization (FISH) was applied to precise the abnormality.     ///    "FISH revealed a complex rearrangement involving chromosomes 7, 21 and 8, and involvement of the AML1 gene without evidence of AML1-ETO fusion. "