AUTHOR=Ahmed Sonia , Elsherif Mariam , Yassin Dina , Elsharkawy Nahla , Mohamed Ayman S. , Yasser Nouran , Elnashar Amr , Hafez Hanafy , Kolb Edward A. , Elhaddad Alaa 

TITLE=Integration of measurable residual disease by WT1 gene expression and flow cytometry identifies pediatric patients with high risk of relapse in acute myeloid leukemia

JOURNAL=Frontiers in Oncology

VOLUME=14

YEAR=2024

URL=https://www.frontiersin.org/journals/oncology/articles/10.3389/fonc.2024.1340909

DOI=10.3389/fonc.2024.1340909

ISSN=2234-943X

ABSTRACT=<sec><title>Background</title><p>Molecular testing plays a pivotal role in monitoring measurable residual disease (MRD) in acute myeloid leukemia (AML), aiding in the refinement of risk stratification and treatment guidance. Wilms tumor gene 1 (<italic>WT1</italic>) is frequently upregulated in pediatric AML and serves as a potential molecular marker for MRD. This study aimed to evaluate <italic>WT1</italic> predictive value as an MRD marker and its impact on disease prognosis.</p></sec><sec><title>Methods</title><p>Quantification of <italic>WT1</italic> expression levels was analyzed using the standardized European Leukemia Network real-time quantitative polymerase chain reaction assay (qRT-PCR) among a cohort of 146 pediatric AML patients. Post-induction I and intensification I, MRD response by <italic>WT1</italic> was assessed. Patients achieving a ≥2 log reduction in <italic>WT1</italic>MRD were categorized as good responders, while those failing to reach this threshold were classified as poor responders.</p></sec><sec><title>Results</title><p>At diagnosis, <italic>WT1</italic> overexpression was observed in 112 out of 146 (76.7%) patients. Significantly high levels were found in patients with M4- FAB subtype (p=0.018) and core binding fusion transcript (CBF) (<italic>RUNX1::RUNX1T1</italic>, p=0.018, <italic>CBFB::MYH11</italic>, p=0.016). Following induction treatment, good responders exhibited a reduced risk of relapse (2-year cumulative incidence of relapse [CIR] 7.9% <italic>vs</italic> 33.2%, p=0.008). Conversely, poor responders’ post-intensification I showed significantly lower overall survival (OS) (51% <italic>vs</italic> 93.2%, p&lt;0.001), event-free survival (EFS) (33.3% <italic>vs</italic> 82.6%, p&lt;0.001), and higher CIR (66.6% <italic>vs</italic> 10.6%, p&lt;0.001) at 24 months compared to good responders. Even after adjusting for potential confounders, it remained an independent adverse prognostic factor for OS (p=0.04) and EFS (p=0.008). High concordance rates between <italic>WT1</italic>-based MRD response and molecular MRD were observed in CBF patients. Furthermore, failure to achieve either a 3-log reduction by RT-PCR or a 2-log reduction by <italic>WT1</italic> indicated a high risk of relapse. Combining MFC-based and <italic>WT1</italic>-based MRD results among the intermediate-risk group identified patients with unfavorable prognosis (positive predictive value [PPV] 100%, negative predictive value [NPV] 85%, and accuracy 87.5%).</p></sec><sec><title>Conclusion</title><p><italic>WT1</italic>MRD response post-intensification I serves as an independent prognostic factor for survival in pediatric AML. Integration of <italic>WT1</italic> and MFC-based MRD results enhances the reliability of MRD-based prognostic stratification, particularly in patients lacking specific leukemic markers, thereby influencing treatment strategies.</p></sec>