Use of the polymerase chain reaction in the detection of AML1/ETO fusion transcript in t(8;21).
BACKGROUND
t(8;21)(q22;q22), found in acute myeloid leukemia (AML) and occasionally in myelodysplasia (MDS), results in the fusion of the AML1 gene on 22q22 to the ETO gene on 8q22, generating a chimeric AML1/ETO transcript, which is a molecular marker of the translocation.


METHODS
Reverse transcription-polymerase chain reaction (RT-PCR), with two pairs of nested AML1 and ETO primers, was used to amplify the AML1/ETO fusion transcript. The Kasumi-1 cell line was used as a positive control.


RESULTS
RT-PCR has a sensitivity of 0.0001% (10(-6)), corresponding to detection of 0.5 picograms of leukemic RNA in the presence of 0.5 micrograms of normal RNA. Using this approach, patients with t(8;21) (three patients with de novo AML, one with therapy-related AML, and one patient with myelodysplasia) yielded the same 222 base pair PCR product, suggesting that the breakpoints occurred at the same AML1 and ETO introns as previously reported. Three patients were still PCR-positive when in complete remission after chemotherapy and two experienced relapse. However, in another three patients with t(8;21) who were in remission for 2 months, 2 years, and 3 1/2 years, respectively, PCR was negative.


CONCLUSIONS
RT-PCR is a sensitive method of detection of t(8;21), and is useful in the monitoring of minimal residual leukemia. As the junction of AML1/ETO appears to be constant, RT-PCR may offer a quick and accurate diagnosis of t(8;21).
Kwong
Y L
YL
University Department of Medicine, Queen Mary Hospital, Hong Kong.
Chan
V
V
Wong
K F
KF
Chan
T K
TK
D000328:Adult; D001483:Base Sequence; D002891:Chromosomes, Human, Pair 21; D002898:Chromosomes, Human, Pair 8; D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins / Q000235:genetics*; D005260:Female; D006801:Humans; D015470:Leukemia, Myeloid, Acute / Q000235:genetics / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009190:Myelodysplastic Syndromes / Q000235:genetics / Q000378:metabolism; D009363:Neoplasm Proteins / Q000235:genetics*; D018365:Neoplasm, Residual; D015514:Oncogene Proteins, Fusion / Q000235:genetics*; D016133:Polymerase Chain Reaction; D011518:Proto-Oncogene Proteins; D012334:RNA, Neoplasm / Q000032:analysis*; D000075142:RUNX1 Translocation Partner 1 Protein; D012680:Sensitivity and Specificity; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic; D014178:Translocation, Genetic
D050676:Core Binding Factor Alpha 2 Subunit; D004268:DNA-Binding Proteins; D009363:Neoplasm Proteins; D015514:Oncogene Proteins, Fusion; D011518:Proto-Oncogene Proteins; D012334:RNA, Neoplasm; D000075142:RUNX1 Translocation Partner 1 Protein; C493728:RUNX1 protein, human; C082222:RUNX1T1 protein, human; D014157:Transcription Factors