To examine the prognostic significance of minimal residual disease (MRD) in t(8;21) acute myeloid leukemia (AML), 96 bone marrow samples from 26 Japanese patients in complete remission (CR) were analyzed regarding the RUNX1/MTG8 transcript using real-time reverse transcriptase polymerase chain reaction assay.
The results suggest that we may easily monitor MRD in patients with t(8;21) AML through quantitative analysis of AML1-ETO transcripts in blood samples.
Most sensitive methodology to detect MRD is molecular polymerase chain reaction (PCR) but its applicability is restricted to AML with leukemia-specific molecular targets (e.g.AML1-ETO, CBFB-MYH11, MLL, FLT-3).
Since AML1/MTG8 fusion transcripts remain detectable by RT-PCR in t(8;21) AML patients in long-term hematological remission, quantitative assessment of AML1/MTG8 transcripts is necessary for the monitoring of minimal residual disease (MRD) in these patients.
Here we studied minimal residual disease (MRD) of patients with acute myeloid leukemia (AML) who have PML/RAR alpha or AML1/ETO as well as the phenotypic analysis of lymphocyte subsets involved in antitumor immunity.
In core binding factor (CBF) acute myeloid leukaemia (AML), realtime quantitative PCR is useful to quantify the fusion transcript ratio (CBFβ-MYH11 and AML1-ETO, in case of inv(16) and t(8;21) respectively) in peripheral blood and bone marrow during the courses of chemotherapy, in order to monitor minimal residual disease (MRD).
The genes PML and AML1, and ETO were examined in normal hematopoietic progenitors and their fusions proteins, PML/RAR alpha and AML1/ETO, measured in patients in clinical remission, and important data were presented concerning these proteins and measurement of minimal residual disease.
Simultaneous monitoring of MRD by RT-PCR using primers for specific DNA markers in 3 patients (2 AML-M3 with PML/RAR alpha, and 1 AML-M2 with AML1/ETO) among these 9 patients detected MRD comparable with that obtained from quantitation of WT1 gene expression.
Recently, we have developed a quantitative assay using competitive reverse transcriptase polymerase chain reaction that estimates the number of AML1/ETO transcripts in t(8;21) acute myelogenous leukemia (AML), in order to determine the degree of leukemic cell contamination in PBSC harvests, and to monitor minimal residual disease (MRD) quantitatively in patients with t(8;21) AML.
We have developed a titration assay using a competitive reverse transcriptase polymerase chain reaction (RT-PCR) which is able to estimate the number of AML1/ETO transcripts so that minimal residual disease (MRD) can be monitored quantitatively in patients with t(8;21) acute myelogenous leukaemia (AML).
Comparative monitoring of MRD by RQ-PCR for the Wilms' tumor gene 1(WT1) or specific translocation markers demonstrated that BAALC had similar kinetics as WT1, AML1/ETO and minor BCR/ABL, but not PML/RARA.
Areas covered: Available techniques include multi-color flow cytometry (MFC) of leukemia associated immunophenotypes (LAIP), quantitative reverse transcriptase polymerase chain reaction (QRT-PCR) for detecting fusion and mutated genes (RUNX1-RUNX1T1, CBFB-MYH11, and NPM1), overexpression of genes such as WT1, and next generation sequencing (NGS) for MRD.
We quantified MRD at various time points during and after therapy by real-time reverse transcriptase polymerase chain reaction (RT-PCR) for AML1/MTG8 and CBFB/MYH11 in 37 patients with CBF leukemias treated within a multicenter trial.
We hypothesized that the overexpression of the MTG8 gene in t(8;21) AML cells could act as a possible tumour antigen, which might be able to induce the immune-mediated suppression of the expansion of MRD.
Thus, the presence of AML1/ETO in this case appeared to be due to persistence of the mutated clone as mature myeloid cells instead ofMRD, implying that the t(8;21) had occurred in a preleukemic myeloid progenitor cell capable of differentiation.
To determine the prognostic significance of the detection of the minimal residual disease (MRD) in children with AML1/ETO AML, we compared the results of reverse-transcription polymerase chain reaction (RT-PCR) and quantitative reverse-transcription polymerase chain reaction (RQ-PCR).
We identified that poor-risk karyotype showed very poor outcome after auto-HCT, and then analyzed 85 patients with good to intermediate-risk molecular cytogenetics with available molecular study results and markers for minimal residual disease (MRD) such as WT1 and core-binding factor (CBF) associated MRD (ie, AML1/ETO and CBFβ/MYH11).
Patients with < 3-log reduction in the RUNX1-RUNX1T1 transcript level after the second consolidation therapy (defined as MRD-H) had a significantly lower 2-year RFS rate than patients with ≥ 3-log reduction (MRD-L) (P = .017).
Because the PCR detection of the AML1/MTG8(ETO) fusion at the RNA level is highly sensitive, it can be used as a sensitive method for diagnosis and detection of minimal residual disease in t(8;21) leukemia.
We asked whether minimal residual disease (MRD) determined by RUNX1/RUNX1T1 transcript levels could identify allogeneic hematopoietic stem cell transplantation (allo- HSCT) t(8;21) (q22;q22) acute myeloid leukemia patients who are at high risk for relapse, together with the impact of c-KIT mutations.
These results indicate that RT-PCR amplification of the AML1/ETO fusion transcript is a powerful tool for diagnosing and monitoring minimal residual disease in AML-M2 patients.