The initial level of MLL-partial tandem duplication affects the clinical outcomes in patients with acute myeloid leukemia

High WT1 expression predicted induction chemotherapy failure in acute myeloid leukemia patients with non-favorable cytogenetic risk

The prognostic significance of WT1 expression at diagnosis in acute myeloid leukemia (AML) remains obscure, and subgroup analysis is the way for clarification. We previously reported the results in t(8;21) AML. In this study, 437 consecutive adult AML patients with non-favorable cytogenetic risk were enrolled. All patients were tested WT1 transcript levels using real-time quantitative PCR at diagnosis; AML-related common fusion genes, KMT2A-PTD, FLT3-ITD, NPM1, CEBPA and TP53 mutations were simultaneously tested. 92.4% of patients overexpressed WT1 compared to normal bone marrow. The existence of FLT3-ITD, NPM1 mutation and the absence of CEBPA biallelic mutation were significantly related to higher WT1 expression. The cutoff value for WT1 was determined by performing receiver operating characteristic curve analysis in regard to complete remission (CR) achievement and was used to categorize patients into low-expression (WT1-L) and high-expression (WT1-H) groups. In the entire cohort, WT1-H was significantly associated with a lower 1-course and 2-course CR rate (P < 0.0010 and P = 0.0060) but was not related to relapse-free survival (RFS). Multivariate analysis showed that WT1-H was an independent adverse prognostic factor for both 1-course and 2-course CR achievement. Subgroup analysis was further performed. WT1-H had a significant adverse impact on CR achievement within intermediate-cytogenetic risk, high-cytogenetic risk, ELN-defined-intermediate-risk, normal karyotype, KMT2A rearrangement, FAB-M2, FAB-M5 and NPM1 mutation (+) subgroups, whereas it had no impact within ELN-defined-low-risk, ELN-defined-high-risk, FAB-M4, FLT3-ITD mutation (+) and CEBPA biallelic mutation (+) subgroups. Moreover, WT1-H patients had a significantly lower RFS rate than WT1-L patients within both FAB-M5 and KMT2A rearrangement subgroups (P = 0.010 and 0.028), whereas WT1 had no impact on RFS within other subgroups mentioned above (all P > 0.05). Therefore, high WT1 expression at diagnosis independently predicted induction chemotherapy failure in AML patients with non-favorable cytogenetic risk, and it was related to relapse just within FAB-M5 and KMT2A rearrangement subgroups.

Optical Genome Mapping in Routine Cytogenetic Diagnosis of Acute Leukemia

Cytogenetic aberrations are found in 65% of adults and 75% of children with acute leukemia. Specific aberrations are used as markers for the prognostic stratification of patients. The current standard cytogenetic procedure for acute leukemias is karyotyping in combination with FISH and RT-PCR. Optical genome mapping (OGM) is a new technology providing a precise identification of chromosomal abnormalities in a single approach. In our prospective study, the results obtained using OGM and standard techniques were compared in 29 cases of acute myeloid (AML) or lymphoblastic leukemia (ALL). OGM detected 73% (53/73) of abnormalities identified by standard methods. In AML cases, two single clones and three subclones were missed by OGM, but the assignment of patients to cytogenetic risk groups was concordant in all patients. OGM identified additional abnormalities in six cases, including one cryptic structural variant of clinical interest and two subclones. In B-ALL cases, OGM correctly detected all relevant aberrations and revealed additional potentially targetable alterations. In T-ALL cases, OGM characterized a complex karyotype in one case and identified additional abnormalities in two others. In conclusion, OGM is an attractive alternative to current multiple cytogenetic testing in acute leukemia that simplifies the procedure and reduces costs.

The adverse impact of ecotropic viral integration site-1 (EVI1) overexpression on the prognosis of acute myeloid leukemia with KMT2A gene rearrangement in different risk stratification subtypes

INTRODUCTION

AML patients with KMT2A-MLLT3 and other 11q23 abnormalities belong to the intermediate and high-risk level groups, respectively. Whether the poor prognostic value of Ecotropic Viral Integration site-1 (EVI1) overexpression suits either the subtypes of KMT2A-MLLT3 or Non-KMT2A-MLLT3 AML patients (intermediate and high risk group) needs to be further investigated.

METHODS

We retrospectively analyzed the clinical characteristics of 166 KMT2A-r and KMT2A-PTD AML patients.

RESULTS

For the Non-KMT2A-MLLT3 group, patients in the EVI1-high subgroup had shorter OS and DFS and higher CIR than those in the EVI1-low subgroup (p = .027, p = .018, and p = .020, respectively). Additionally, both KMT2A-MLLT3 and Non-KMT2A-MLLT3 patients who received chemotherapy alone had poorer prognosis than patients who also received allogeneic hematopoietic stem cell transplant (allo-HSCT) regardless of their EVI1 expression level (all p < .001). For transplanted patients with KMT2A-MLLT3 or Non-KMT2A-MLLT3 rearrangement, the EVI1-high subgroup had worse prognosis than the EVI1-low subgroup (all p < .05). The 2-year CIR of the KMT2A-MLLT3 and Non-KMT2A-MLLT3 groups with high EVI1 expression was high (52% and 49.6%, respectively). However, for patients with low EVI1 expression, the 2-year CIR of transplanted patients with KMT2A-MLLT3 and Non-KMT2A-MLLT3 was relatively low.

CONCLUSIONS

Our study showed that for the Non-KMT2A-MLLT3 group, the EVI1-high group had shorter OS and DFS than the EVI1-low group. High EVI1 expression showed an adverse effect in AML with KMT2A rearrangement in different risk stratification subtypes. For the EVI1-high patients with non-KMT2A-MLLT3 rearrangement, other novel regimens towards relapse should be taken into consideration.

Prognostic significance of KMT2A-PTD in patients with acute myeloid leukaemia: a systematic review and meta-analysis

OBJECTIVES

Whether KMT2A-PTD has a prognostic impact on patients with acute myeloid leukaemia (AML) is controversial. Therefore, we conducted a meta-analysis to assess the prognostic value of KMT2A-PTD in patients with AML.

METHODS

Eligibility criteria: we included studies concerning the prognostic value of KMT2A-PTD in patients with AML.

INFORMATION SOURCES

Eligible studies were identified from PubMed, Embase, Medline, Web of Science, Cochrane Library and Chinese Biomedical Database. The systematic search date was 19 December 2020.Risk of bias: Sensitivity analysis was used to evaluate the stability and reliability of the combined results. Begg's and Egger's tests were used to assess the publication biases of studies.

SYNTHESIS OF RESULTS

We calculated the pooled HRs and their 95% CIs for overall survival (OS) and event-free survival (EFS) by Stata V.12 software.

RESULTS

Included studies: 18 studies covering 6499 patients were included.

SYNTHESIS OF RESULTS

KMT2A-PTD conferred shorter OS in total population (HR=1.30, 95% CI 1.09 to 1.51). In the subgroup analysis, KMT2A-PTD also resulted in shorter OS in karyotypically normal AML patients (HR=2.72, 95% CI 1.83 to 3.61) and old AML patients (HR=1.93, 95% CI 1.44 to 2.42). KMT2A-PTD indicated no prognostic impact on EFS in total population (HR=1.26, 95% CI 0.86 to 1.66). However, in the sensitivity analysis, KMT2A-PTD resulted in poor EFS (HR=1.34, 95% CI 1.04 to 1.64) when deleting the study with a relatively obvious effect on the combined HR. In the subgroup analysis, KMT2A-PTD was associated with poor EFS in old AML patients (HR=1.64, 95% CI 1.25 to 2.03).

CONCLUSION

The findings indicated that KMT2A-PTD had an adverse impact on the prognosis of patients with AML in the total population, and the conclusion can also be applied to some subgroups including karyotypically normal AML and old AML patients. KMT2A-PTD may be a promising genetic biomarker in patients with AML in the future.

TRIAL REGISTRATION NUMBER

CRD42021227185.

Allelic Complexity of KMT2A Partial Tandem Duplications in Acute Myeloid Leukemia and Myelodysplastic Syndromes

KMT2A-PTD undergo complex allelic events associated with advanced disease stage (AML over MDS), progression, and increased PTD expression.

KMT2A-PTD detection, quantification, and allelic characterization can be integrated into standard panel-based DNA sequencing tests.

KMT2A partial tandem duplication (KMT2A-PTD) is an adverse risk factor in acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), a potential therapeutic target, and an attractive marker of measurable residual disease. High initial KMT2A-PTD RNA levels have been linked to poor prognosis, but mechanisms regulating KMT2A-PTD expression are not well understood. Although KMT2A-PTD has been reported to affect only a single allele, it has been theorized but not proven that genomic gains of a monoallelic KMT2A-PTD may occur, thereby potentially driving high expression and disease progression. In this study, we identified 94 patients with KMT2A-PTDs using targeted DNA next-generation sequencing (NGS) and found that 16% (15/94) had complex secondary events, including copy-neutral loss of heterozygosity and selective gain involving the KMT2A-PTD allele. High copy numbers indicating complexity were significantly enriched in AML vs MDS and correlated with higher RNA expression. Moreover, in serial samples, complexity was associated with relapse and secondary transformation. Taken together, we provide approaches to integrate quantitative and allelic assessment of KMT2A-PTDs into targeted DNA NGS and demonstrate that secondary genetic events occur in KMT2A-PTD by multiple mechanisms that may be linked to myeloid disease progression by driving increased expression from the affected allele.

Monitoring of post-transplant MLL-PTD as minimal residual disease can predict relapse after allogeneic HSCT in patients with acute myeloid leukemia and myelodysplastic syndrome

Background

The mixed-lineage leukemia (MLL) gene is located on chromosome 11q23. The MLL gene can be rearranged to generate partial tandem duplications (MLL-PTD), which occurs in about 5-10% of acute myeloid leukemia (AML) with a normal karyotype and in 5-6% of myelodysplastic syndrome (MDS) patients. Allogeneic hematopoietic stem cell transplantation (allo-HSCT) is currently one of the curative therapies available for AML and MDS with excess blasts (MDS-EB). However, how the prognosis of patients with high levels of MLL-PTD after allo-HSCT, and whether MLL-PTD could be used as a reliable indicator for minimal residual disease (MRD) monitoring in transplant patients remains unknown. Our study purposed to analyze the dynamic changes of MLL-PTD peri-transplantation and the best threshold for predicting relapse after transplantation.

Methods

We retrospectively collected the clinical data of 48 patients with MLL-PTD AML or MDS-EB who underwent allo-HSCT in Peking University People’s Hospital. The MLL-PTD was examined by real-time quantitative polymerase chain reaction (RQ-PCR) at the diagnosis, before transplantation and the fixed time points after transplantation. Detectable MLL-PTD/ABL > 0.08% was defined as MLL-PTD positive in this study.

Results

The 48 patients included 33 AML patients and 15 MDS-EB patients. The median follow-up time was 26(0.7-56) months after HSCT. In AML patients, 7 patients (21.2%) died of treatment-related mortality (TRM), 6 patients (18.2%) underwent hematological relapse and died ultimately. Of the 15 patients with MDS-EB, 2 patients (13.3%) died of infection. The 3-year cumulative incidence of relapse (CIR), overall survival (OS), disease-free survival (DFS) and TRM were 13.7 ± 5.2, 67.8 ± 6.9, 68.1 ± 6.8 and 20.3% ± 6.1%, respectively. ROC curve showed that post-transplant MLL-PTD ≥ 1.0% was the optimal cut-off value for predicting hematological relapse after allo-HSCT. There was statistical difference between post-transplant MLL-PTD ≥ 1.0% and MLL-PTD < 1.0% groups (3-year CIR: 75% ± 15.3% vs. 0%, P < 0.001; 3-year OS: 25.0 ± 15.3% vs. 80.7% ± 6.6%, P < 0.001; 3-year DFS: 25.0 ± 15.3% vs. 80.7 ± 6.6%, P < 0.001; 3-year TRM: 0 vs. 19.3 ± 6.6%, P = 0.277). However, whether MLL-PTD ≥ 1% or MLL-PTD < 1% before transplantation has no significant difference on the prognosis.

Conclusions

Our study indicated that MLL-PTD had a certain stability and could effectively reflect the change of tumor burden. The expression level of MLL-PTD after transplantation can serve as an effective indicator for predicting relapse.

The Application of Targeted RNA Sequencing for KMT2A-Partial Tandem Duplication Identification and Integrated Analysis of Molecular Characterization in Acute Myeloid Leukemia

The partial tandem duplication of histone-lysine N-methyltransferase 2A (KMT2A-PTD) is an important genetic alteration in acute myeloid leukemia (AML) and is associated with poor clinical outcome. Accurate and rapid detection of KMT2A-PTD is important for outcome prediction and clinical management, but next-generation sequencing-based quantitative research is still lacking. In this study, we developed a targeted RNA-based next-generation sequencing panel, together with single primer enrichment and unique molecular identifiers, to identify KMT2A-PTD as well as AML-related gene fusions and other driver mutations. Our panel showed high sensitivity, accuracy, and reproducibility in detecting the fusion ratio of KMT2A-PTD. We characterized the mutation profile of KMT2A-PTD-positive patients with AML and found different distribution patterns of driver mutations according to KMT2A-PTD fusion ratio level. Survival analyses revealed that the fusion ratio of KMT2A-PTD did not affect clinical outcome, but a novel molecular combination, namely, KMT2A-PTD/DNMT3A/FMS-like tyrosine kinase 3-internal tandem duplication, was associated with poor prognosis. Finally, we proved that the dynamic changes in the KMT2A-PTD fusion ratio were consistent with the overall process of disease progression. In summary, we applied the unique molecular identifier-based RNA panel to quantitatively detect KMT2A-PTD and elucidate its clinical relevance, which complemented the integrative network of various genetic alterations in AML.

Prognostic significance of microRNA-99a in acute myeloid leukemia patients undergoing allogeneic hematopoietic stem cell transplantation

Overexpression of microRNA-99a (miR-99a) have been associated with adverse prognosis in acute myeloid leukemia (AML). Nevertheless, whether it also predicts poor outcome in post-allogeneic hematopoietic stem cell transplantation (allo-HSCT) AML patients remains unclear. To further elucidate the prognostic value of miR-99a, 74 AML patients with miR-99a expression report who underwent allo-HSCT from The Cancer Genome Atlas database were identified and grouped into either miR-99a^high or miR-99a^low based on their miR-99a expression levels relative to the median. Two groups had similar clinical and molecular characteristics except that miR-99a^high group had fewer patients of the French-American-British M4 subtype (P = 0.018) and more frequent CEBPA mutations (P = 0.005). Univariate analysis indicated that high miR-99a expression was unfavorable for both event-free survival (EFS) and overall survival (OS; P = 0.029; P = 0.012, respectively). Multivariate analysis suggested that high miR-99a expression was an independent risk factor for both EFS and OS in AML patients who underwent allo-HSCT [hazard ratio (HR) 1.909, 95% confidence interval (CI) 1.043-3.494, P = 0.036 and HR 2.179, 95% CI 1.192-3.982, P = 0.011, respectively]. Our results further proved that high miR-99a expression could predict worse outcome in AML patients, even in those who underwent intensive post-remission therapy such as allo-HCST.