Creation of functional AML1-ETO fusion genes in these two simple variant t(8;21) probably occurred through complex mechanisms, combining translocation and insertion of chromosomal segments..     ///    "However, dual-color FISH using appropriate ETO and AML1 probes disclosed an insertion of AML1 into 8q22 on the derivative chromosome 8 in patient 1 and of ETO into 21q22 on one chromosome 21 in patient 2, leading to AML1-ETO fusion signals. "    ///    "Both cases expressed an AML1-ETO transcript, shown by reverse transcriptase polymerase chain reaction and cDNA sequencing. "