急性骨髓性白血病治療後偵測微量殘存白血病細胞之研究
Other Title
Therapeutic Monitoring of Minimal Residual Disease in Acute
Myelogenous Leukemia
Myelogenous Leukemia
Date Issued
2003
Date
2003
Author(s)
唐季祿
DOI
912314B002180
Abstract
Intensive chemotherapy and bone marrow transplantation have achieve high complete
remission rate (60~80%) and 30-70% long-term survivor in acute myeloid leukemia (AML).
However, many patients still died of relapse eventually. In the past 2 years, we have developed a
real-time quantitative RT-PCR (RQ-PCR) assay that can accurately detect one leukemic cell out
of 10 4 to 10 5 normal cells (4-5 Log) with 100% specificity. This assay was highly correlated with
leukemic status and was able to identify high-risk patients before clinical relapse occurred.
However, this technique is applicable to 20-30% of AML patients with specific molecular fusion
genes—AML1-ETO in t(8;21) and PML-RAR α in t(15;17). Recently, WT-1 gene, gene
responsible for Wilms’ tumor, was found to be over-expressed in 60-80% of AML and was
associated with poor survivor. Quantitation of WT-1 RNA level may be a candidate molecular
target useful in monitoring the level of minimal residual leukemia (MRL) after treatment.
The goal of this project is to extend our current technique in using RQ-PCR in therapeutic
monitoring of more than 50% of AML patients which have important clinical utility in detecting residual leukemia, selecting high risk patients and predicting leukemic relapse.
In a retrospective study between Jan. 2000 and Apr. 2003, WT1 expression level in 84 adult
AML at diagnosis was performed by a novel one-step multiplex quantitative real time reverse
transcriptase polymerase chain reaction (M-RQ-PCR) technique. WT1 overexpression was
defined as ≧ 1% expression level of K562 cell line.
Normal samples collected from 3 BMT and 11 PBSCT donors contained very low or
undetectable levels of WT1, suggesting that normal stem cells expressed very low level of WT1.
WT1 overexpression was detected in 65/84 (77%) AML and 5/7 (71%) ALL and were eligible for
MRD monitoring. There was no association of WT1 expression level with sex, age, initial WBC
counts, CD34%, blast%, and cytogenetics. WT1 overexpression occurred frequently in most FAB
subtypes except for M5 subtype. In 5 AML patients with both t(8;21) and WT1 overexpression,
MRD level was estimated by AML1-ETO RQ-PCR and WT1 RQ-PCR assays respectively and
there was good linear correlation (r 2 =0.769, N=35). In some cases, WT1 level was useful in
differential diagnosis of early relapse. False negative results may be encountered in poor quality
samples and should be interpreted cautiously. Serial follow-up of WT1 kinetics in 52 patients
showed that WT1-MRD level persistently > 10 -3 after chemotherapy was associated with
leukemic relapse. By contrast, relapse occurred in some patients who initially achieved molecular
remission.
In conclusion, WT1 RQ-PCR assay is potentially useful molecular marker for MRD
monitoring in AML patients. Whether WT1 level after induction and consolidation therapy is
correlated with relapse risk and clinical outcome deserves further study.
Subjects
acute myeloid leukemia
minimal residual leukemia
real-time RT-PCR
WT-1 gene
Publisher
臺北市：國立臺灣大學醫學院內科
Type
report
File(s)![Thumbnail Image]()
Loading...
Name
912314B002180.pdf
Size
173.27 KB
Format
Adobe PDF
Checksum
(MD5):c3f3d95a767259b3d54e2f01d7f96588