 The chromosomal translocation t(8;21) (q22;q22) is often associated with acute myeloid leukemia with maturation (AML-M2) and can be detected by a reverse transcription-polymerase chain reaction (RT-PCR) for the AML1/ETO fusion mRNA.     ///    AML1/ETO was also detected in two AML patients lacking the t(8;21) cytogenetically.     ///    We investigated the prevalence of t(8;21) and AML1/ETO in 204 unselected patients with AML and compared the results of cytogenetic analysis with these of RT-PCR.     ///    In 17 of 204 patients (8.3%) AML1/ETO was detected by RT-PCR.     ///    Comparison of karyotype analysis and RT-PCR for AML1/ETO in 204 unselected patients with AML..     ///    "These data indicate that the results of karyotyping and RT-PCR are not completely identical, and molecular biology identifies approximately an additional 5-10% of AML1/ETO positive cases. "