Detection of Residual Leukemia with Reverse Transcription-polymerase Chain Reaction from Patients with AML1/ETO Positive Acute Myeloid Leukemia in Remission

Park, Kyoung Bun; Lee, Jae Jin; Yoon, Hwi Joong; Kim, Si Young; Kim, Young Il; Cho, Kyoung Sam

Abstract

BACKGROUND
One of the most frequent cytogenetic abnormality in acute myeloid leukemia (AML) is t(8;21) (q22;q22), with rearrangement of the AML1 gene on chromosome 21q22 and the ETO gene on chromosome 8q22. In adult AML1/ETO-associated leukemia patients, chemotherapy alone results in cure rates that are comparable to or better than those achieved with allogenic bone marrow transplantation. Despite the relatively good prognosis of AML1/ETO fusion transcript, relapse of leukemia remains the most common cause of treatment failure. Monitoring minimal residual disease (MRD) in leukemia has two main aims : to assess the effectiveness of treatment and to detect early signs of relapse. Reverse transcription-polymerase chain reaction (RT-PCR)- based methods is the rapid and sensitive method in the identification of this molecular abnormality. The purpose of this study is to ensure the usefulness of the RT-PCR technique for detecting MRD in AML1/ETO-associated leukemia patients in remission and to establish the correlation of the serial detection of AML1/ETO fusion transcripts after complete remission and long-term outcome.
METHODS
From the bone marrow aspirates of 25 AML1/ETO positive AML patients, serial detection of AML1/ETO fusion trascripts was performed using RT-PCR.
RESULTS
AML1/ETO fusion transcripts were positive in 14 cases who did not show t(8;21). In serial assay, AML1/ETO fusion transcripts was positive in 9 cases and negative in 13 cases at 10 weeks after complete remission. AML1/ETO fusion transcripts (+) group has 107.4+/-18.2 months suvival and AML1/ETO fusion transcripts (-) group has 47.3+/-18.0 months survival. However, there is no significance (P=0.11).
CONCLUSION
This study suggests that the early negative conversion of AML1/ETO fusion transcript may be the good prognostic predictor. The RT-PCR technique is useful for detecting minimal residual disease in leukemia patients in remission and it may improve the therapeutic strategy for leukemia.