ABSTRACT
Objective To develop a method of real-time quantitative polymerase chain reaction (RQ-PCR) for detection of translocation ETS leukemia-acute myeloid leukemia 1(TEL-AML1) fusion gene in children with acute lymphoblast leukemia(ALL),and explore its clinical application in minimal residual disease (MRD) monitoring.Methods By reverse transcription and RQ-PCR,a quantifying of TEL-AML1 fusion gene was developed,and the expression levels of TEL-AML1 were detected in bone marrow (BM) samples obtained from 24 children with ALL at diagnosis and at the end of induction of remission,as well as at a series of follow-up. Moreover,the results of MRD detection by RQ-PCR were compared with that of detection by routine morphological examine of BM and cells differentiation mark analysis by flow cytometer(FCM),to evaluate the sensitivity of RQ-PCR in MRD monitoring. Results A method of RQ-PCR targeted at TEL-AML1 fusion gene was established. In 11 BM samples,which collected from TEL-AML1 positive children at the end of induction therapy and all of them achieved completely remission (CR) by routine morphological examine,5 samples were found to be MRD positive by RQ-PCR,positive ratio was 45%. There were 15 BM samples collected in maintenance therapy period,and all these samples were CR by routine morphological examine. However,by RQ-PCR,3 out of 15 samples were found to be MRD positive during maintenance therapy period. After intense and maintenance therapy,the MRD levels of the 3 children were declined to negative. In a recrudescent child,the expression of TEL-AML1 fusion gene was rose by a magnitude of 103 copies before relapse,and after induction therapy once again the patient was completely relaxed.Conclusions RQ-PCR targeted at TEL-AML1 has a higher sensitivity than conventional morphologic way and FCM. RQ-PCR can be used in the quantitative detection of MRD,and provide gist for early prognosticating a relapse and instructing clinical therapy.