Wilms Tumor 1 Expression at Diagnosis Correlates With Genetic Abnormalities and Polymorphism But Is Not Independently Prognostic in Acute Myelogenous Leukemia: A Hokkaido Leukemia Net Study

Clinical significance of WT1 in the evaluation of therapeutic effect and prognosis of non-M3 acute myeloid leukemia

To explore the clinical significance and prognosis of acute myeloid leukemia (AML) patients with WT1 mutations.In total, the clinical data of 269 adult patients with non-M3 AML were considered retrospectively. From these patients, 153 carried WT1 mutation whereas 116 were negative. WT1 mutation positive patients were further divided into WT1 low expression and high expression groups base on the expression level of WT1 by qPCR at diagnosis (cut off: 170500). Survival and therapeutic effect analysis were performed for the above patients with different interfering factors such as co-mutations, the extent of WT1 log reduction and the chemotherapy regimens. Patients with high WT1 expression have higher rate of relapse. We can accurately identify patients with inferior outcomes when we take the following factors into consideration: the WT1 expression level at diagnosis; different prognostic factors including co-mutations (especially NPM1 and FLT3-ITD); the log reduction of WT1 after induction therapy and the risk of stratification. Idarubicin + Cytarabine (IA) regimen could reduce the expression level of WT1 after treatment, and Allo-HSCT played an important role in improving the prognosis of patients with WT1 high expression and patients with WT1 negativity. Among the relapsed patients, there existed a rising trend of WT1-MRD in advance than MFC-MRD and that of patients with continuous complete remission (CR). Different clinical background should be taken into consideration when we judge the prognosis and therapeutic effect of patients with WT1 mutations. In addition, WT1 may be an optional MRD marker, which needs regular monitoring.

Wilms' tumor gene 1 in hematological malignancies: friend or foe?

Wilms' tumor gene 1 (WT1) is a transcription and post-translational factor that has a crucial role in the biological and pathological processes of several human malignancies. For hematological malignancies, WT1 overexpression or mutation has been found in leukemia and myelodysplastic syndrome. About 70-90% of acute myeloid leukemia patients showed WT1 overexpression, and 6-15% of patients carried WT1 mutations. WT1 has been widely regarded as a marker for monitoring minimal residual disease in acute myeloid leukemia. Many researchers were interested in developing WT1 targeting therapy. In this review, we summarized biological and pathological functions, correlation with other genes and clinical features, prognosis value and targeting therapy of WT1 in hematological features.

Clinical implications of NUP98::NSD1 fusion at diagnosis in adult FLT3-ITD positive AML

OBJECTIVES

The cryptic fusion oncogene NUP98::NSD1 is known to be associated with FLT3-ITD mutation in acute myeloid leukemia (AML), and an independent poor prognostic factor in pediatric AML. However, there are little data regarding the clinical significance of NUP98::NSD1 in adult cohort.

METHODS

We conducted a multicenter retrospective study to investigate the prevalence, clinical characteristics, and prognostic impact of NUP98::NSD1 in adult FLT3-ITD-positive AML patients.

RESULTS

In a total of 97 FLT3-ITD-positive AML patients, six cases (6.2%) were found to harbor the NUP98::NSD1 fusion transcript. NUP98::NSD1 positive cases had significantly higher platelet counts and a higher frequency of FAB-M4 morphology than NUP98::NSD1 negative cases. NUP98::NSD1 was found to be mutually exclusive with NPM1 mutation, and was accompanied by the WT1 mutation in three of the six cases. The presence of NUP98::NSD1 fusion at the time of diagnosis predicted poor response to cytarabine-anthracycline-based intensive induction chemotherapy (induction failure rate: 83% vs. 36%, p = .038). Five of the six cases with NUP98::NSD1 underwent allogeneic hematopoietic stem cell transplantation (HSCT). Two of the five cases have successfully maintained remission, with one of them being rescued through a second HSCT.

CONCLUSIONS

Detecting NUP98::NSD1 in adult FLT3-ITD-positive AML is crucial to recognizing chemotherapy-resistant group.

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.

Subclinical minute FLT3-ITD clone can be detected in clinically FLT3-ITD-negative acute myeloid leukaemia at diagnosis

Recent advances in next-generation sequencing (NGS) have enabled the detection of subclinical minute FLT3-ITD. We selected 74 newly diagnosed, cytogenetically normal acute myeloid leukaemia (AML) samples in which FLT3-ITD was not detected by gel electrophoresis. We sequenced them using NGS and found minute FLT3-ITDs in 19 cases. We compared cases with clinically relevant FLT3-ITD (n = 37), cases with minute FLT3-ITD (n = 19) and cases without detectable FLT3-ITD (n = 55). Molecular characteristics (location and length) of minute FLT3-ITD were similar to those of clinically relevant FLT3-ITD. Survival of cases with minute FLT3-ITD was similar to that of cases without detectable FLT3-ITD, whereas the relapse rate within 1 year after onset was significantly higher in cases with minute FLT3-ITD. We followed 18 relapsed samples of cases with clinically FLT3-ITD-negative at diagnosis. Two of 3 cases with minute FLT3-ITD relapsed with progression to clinically relevant FLT3-ITD. Two of 15 cases in which FLT3-ITD was not detected by NGS relapsed with the emergence of minute FLT3-ITD, and one of them showed progression to clinically relevant FLT3-ITD at the second relapse. We revealed the clonal dynamics of subclinical minute FLT3-ITD in clinically FLT3-ITD-negative AML. Minute FLT3-ITD at the initial AML can expand to become a dominant clone at relapse.

High CRP-albumin ratio predicts poor prognosis in transplant ineligible elderly patients with newly diagnosed acute myeloid leukemia

Acute myeloid leukemia (AML) patients older than 65 years have a poor prognosis. Recently, CAR (C-reactive-protein/albumin ratio) has been actively reported as a prognostic index reflecting the nutritional and inflammatory status of elderly patients with solid tumors, but the usefulness of this index as a prognostic indicator in transplant-ineligible elderly AML patients has not been investigated. We studied genetic alterations and CARs in 188 newly diagnosed AML patients aged 65 years or older who were treated in a multicenter setting and had treated without HSCT. Both NCCN 2017 risk group, reflecting the genetic component of the tumor, and CAR, reflecting the inflammatory and nutritional status of the patient, successfully stratified the overall survival (OS) of the patients (2-year OS; CAR low vs high, 42.3% vs 17.8%, P < 0.001). Furthermore, in multivariate analysis, NCCN 2017 poor group and high CAR were extracted as independent poor prognostic factors predicting 2-year OS in the current study. We found, for the first time, that CAR at diagnosis predicted the prognosis of elderly patients with newly diagnosed AML treated without HSCT.

Dynamic change in peripheral blood WT1 mRNA levels within three cycles of azacitidine predict treatment response in patients with high-risk myelodysplastic syndromes

Azacitidine (AZA) improves overall survival (OS) in patients with high-risk myelodysplastic syndromes (MDS). However, predictive factors for response to AZA remain largely unknown. To elucidate whether dynamic change in peripheral blood (PB) Wilms' Tumor 1 (WT1) mRNA levels could predict response to AZA, we retrospectively identified 75 treatment-naïve patients with high-risk MDS who received at least 3 cycles of AZA. We classified patients into 4 groups, low-increase (LI), low-stable (LS), high-decrease (HD), and high-stable (HS) based on the dynamic change in PB WT1 mRNA levels within 3 cycles of AZA. Cumulative incidence of overall response after 10 cycles of AZA was significantly higher in LS/HD than in HS/LI (75.5% vs 4.5%, P < 0.001). The median OS for LS/HD was 18.2 months (95% CI, 12.8-28.1 months), whereas it was 11.6 months for HS/LI (95% CI, 6.6-14.1 months; P < 0.001). Multivariate analysis demonstrated that poor-/very poor-IPSS-R cytogenetic risk and HS/LI were independently associated with poor OS (poor-/very poor-IPSS-R cytogenetic risk: HR, 2.26; 95% CI, 1.10-4.68, P = 0.03, HS/LI: HR, 2.32; 95% CI, 1.21-4.46, P = 0.01). Patients with HS/LI did not show any further response to continuous AZA, and they should be considered for alternative therapy from earlier cycles.

Non-age-related neoplastic loss of sex chromosome correlated with prolonged survival in real-world CBF-AML patients

In this real-world clinical study, in which we determined eligibility for allogenic hematopoietic stem cell transplantation by prognostic factors and minimal residual disease status, we retrospectively evaluated cytogenetic, genetic, and clinical features in 96 patients with core-binding factor acute myeloid leukemia (CBF-AML) including 62 patients with RUNX1/RUNX1T1 and 34 patients with CBFβ/MYH11. Multivariate analyses for 5-year overall survival (OS) in CBF-AML patients revealed that age of 50 years or older (HR: 3.46, 95% CI 1.47-8.11, P = 0.004) and receiving 2 or more induction cycles (HR: 3.55, 95% CI 1.57-8.05, P = 0.002) were independently associated with worse OS and that loss of sex chromosome (LOS) was independently associated with better OS (HR: 0.09, 95% CI 0.01-0.71, P = 0.022). At the time of complete remission, all 21 karyotyped patients with LOS had a normal karyotype. Furthermore, in all 9 patients with LOS who had a mosaic of metaphase cells with and without t(8;21) or inv(16), the metaphase cells without t(8;21)/inv(16) showed a normal karyotype. These results proved that LOS was not age-related and physiological, but rather a neoplastic chromosomal abnormality.

Clinical values of gene alterations as marker of minimal residual disease in non-M3 acute myeloid leukemia

Acute myeloid leukemia (AML) is a malignant disease of the hematopoietic system. Residual leukemic cells after treatment are associated with relapse. Thus, detecting minimal residual disease (MRD) is significant. Major techniques for MRD assessment include multiparameter flow cytometry (MFC), polymerase chain reaction (PCR), and next-generation sequencing (NGS). At a molecular level, AML is the consequence of collaboration of several gene alterations. Some of these gene alterations can also be used as MRD markers to evaluate the level of residual leukemic cells by PCR and NGS. However, when as MRD markers, different gene alterations have different clinical values. This paper aims to summarize the characteristics of various MRD markers, so as to better predict the clinical outcome of AML patients and guide the treatment.

A novel nutritional index "simplified CONUT" and the disease risk index independently stratify prognosis of elderly patients with acute myeloid leukemia

Elderly patients aged 65 or older with acute myeloid leukemia (AML) have poor prognosis. The risk stratification based on genetic alteration has been proposed in national comprehensive cancer network (NCCN) guideline but its efficacy was not well verified especially in real world elderly patients. The nutritional status assessment using controlling nutritional status (CONUT) score is a prognostic biomarker in elderly patients with solid tumors but was not examined in elderly AML patients. We performed prospective analysis of genetic alterations of 174 patients aged 65 or older with newly diagnosed AML treated without hematopoietic stem cell transplantation (HSCT) and developed simplified CONUT (sCONUT) score by eliminating total lymphocyte count from the items to adapt AML patients. In this cohort, both the NCCN 2017 risk group and sCONUT score successfully stratified the overall survival (OS) of the elderly patients. A multivariable analysis demonstrated that adverse group in NCCN 2017 and high sCONUT score were independently associated with poor 2-year OS. Both risk stratification based on NCCN 2017 and sCONUT score predict prognosis in the elderly patients with newly diagnosed AML.

Short-term treatment with imetelstat sensitizes hematopoietic malignant cells to a genotoxic agent via suppression of the telomerase-mediated DNA repair process

Imetelstat is a specific and competitive inhibitor of telomerase enzymatic activity. We demonstrated that imetelstat could interfere with the DNA repair process and enhance the effect of DNA damaging agents using hematological tumor cell lines. Short-term administration of imetelstat enhanced growth suppression by anticancer agents and radiation. It also upregulated γH2AX expression induced by irradiation. Immunofluorescence staining showed that both human telomerase reverse transcriptase (hTERT) and γH2AX were upregulated and co-localized in the nucleus of peripheral blood mononuclear cells after irradiation, suggesting that hTERT was involved in the DNA-DSB repair process. Imetelstat enhanced growth inhibitory effect of cytotoxic agents in short-term culture without shortening of telomeres, indicating that this effect was attributed by telomere length independent mechanism. Our results suggest that the combination of short-term treatment with imetelstat and cytotoxic agent is a promising strategy to treat a wide variety of hematopoietic malignancies.

Wilms' tumor 1 gene in hematopoietic malignancies: clinical implications and future directions

The Wilms' tumor 1 (WT1) gene is an important regulatory molecule that plays a vital role in cell growth and development. Initially, knowledge of WT1 was mostly limited to Wilms' tumor. Over the past years, numerous studies have shown that WT1 is aberrant expressed or mutated in hematopoietic malignancies, including acute leukemia (AL), myelodysplastic syndrome (MDS) and chronic myelogenous leukemia (CML). Currently, many studies focus on exploring the role of WT1 in hematopoietic malignancies. Such studies improve the understanding of hematopoietic malignancies, and the collection of data about WT1 expression or mutation in hematopoietic malignancies over the past years can facilitate the risk stratification of hematopoietic malignancies. In this review, we highlight the important role of WT1 in hematopoietic malignancies, discuss its potential clinical applications as a minimal residual disease (MRD) and prognostic biomarker, and evaluate the possible therapy target of WT1 in hematopoietic malignancies.

Overexpressed WT1 exhibits a specific immunophenotype in intermediate and poor cytogenetic risk acute myeloid leukemia

Many studies have confirmed that overexpressed WT1 exists in leukemic cells, especially in AML. However, the immunophenotypic features of this sort of leukemic cells remain to be unclarified. We retrospectively analyzed the immunophenotype of 283 newly diagnosed AML patients with intermediated and poor cytogenetic risk to evaluate the correlation between phenotype and WT1 overexpression. EVI1 transcripts, KMT2A-PTD, FLT3-ITD, and NPM1 mutations were simultaneously assessed. Our results revealed that overexpressed WT1 was significantly associated with the expression of CD117, CD13, and CD123. Besides, leukemic cells with WT1 overexpression also lacked lymphoid and myeloid differentiation-related markers. FAB subtype M2 patients had higher WT1 levels, compared with other FAB subtype. Multivariate analysis was proved that NPM1 mutation, M2 subtype, and the expression of CD123 were independently associated with WT1 overexpression. These indicated that AML with overexpressed WT1 was proliferated and blocked in the early stage of AML development. It presumably provided some clues to detect overexpressed WT1 cells via multiparameter flow cytometry. CD123-targeted drugs might become one of the alternative treatments for patients with WT1 overexpression.