Expression of AML1-ETO fusion transcripts and detection of minimal residual disease in t(8;21)-positive acute myeloid leukemia.
The t(8;21) translocation breakpoint, which is observed in acute myeloid leukemia (AML), has recently been cloned and a fusion transcript identified. We have now designed primer sets capable of amplifying the breakpoint junction of the fusion transcript by the reverse transcription-polymerase chain reaction (RT-PCR). Primer set 821U/821D1 amplified a 200-bp DNA fragment, and primer set 821U/821D2 amplified a 1.2-kb DNA fragment in all t(8;21)-positive AML tested. Sequence analysis of the amplified DNA fragments demonstrated that all fusion transcripts were fused at exactly the same site, indicating that this translocation breakpoint occurs within a single intron of the AML1 and ETO genes. Forty-five cycles of RT-PCR were used to detect residual t(8;21)-positive leukemia cells in three patients who had been in complete remission for 1, 3 and 5 years. Minimal residual disease was found in all three samples. Northern blot analysis demonstrated that two fusion transcripts of 7 and 10 kb were expressed in the t(8;21)-positive AML and that the ETO gene is not normally expressed in the hematopoietic system. Expression of a normal 5.5-kb ETO mRNA was found in the lung. From these results we concluded that expression of the ETO gene in t(8;21)-positive AML was activated as a result of the translocation.
Chang
K S
KS
Hematopathology Program, University of Texas M.D. Anderson Cancer Center, Houston 77030.
Fan
Y H
YH
Stass
S A
SA
Estey
E H
EH
Wang
G
G
Trujillo
J M
JM
Erickson
P
P
Drabkin
H
H
D001483:Base Sequence; D002891:Chromosomes, Human, Pair 21; D002898:Chromosomes, Human, Pair 8; D004273:DNA, Neoplasm / Q000032:analysis; D015870:Gene Expression; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000175:diagnosis* / Q000235:genetics; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D016133:Polymerase Chain Reaction; D012334:RNA, Neoplasm / Q000235:genetics; D015183:Restriction Mapping; D014178:Translocation, Genetic
D004273:DNA, Neoplasm; D009838:Oligodeoxyribonucleotides; D012334:RNA, Neoplasm