Epigenomic machinery regulating pediatric AML: clonal expansion mechanisms, therapies, and future perspectives

Epigenetic Reprogramming by Decitabine in Retinoblastoma

INTRODUCTION

Retinoblastoma (Rb) is a rare cancer, yet it is the most common eye tumor in children. It can occur in either a familial or sporadic form, with the sporadic variant being more prevalent, though its downstream effects on epigenetic markers remain largely unclear. Currently, the treatment for retinoblastoma typically involves aggressive chemotherapy and surgical resection. The identification of specific epigenetic characteristics of non-hereditary (sporadic) Rb has led to the development of advanced, high-throughput methods to explore its epigenetic profile. Our previous research demonstrated that treatment with the demethylating agent 5-Aza-2'-deoxycytidine (decitabine; DAC) induced cell cycle arrest and apoptosis in a well-characterized retinoblastoma model (WERI-Rb-1). Our analysis of time-dependent gene expression in WERI-Rb-1 cells following DAC exposure has led to the development of testable hypotheses to further investigate the epigenetic impact on the initiation and progression of retinoblastoma tumors.

METHODS

Gene expression analysis of publicly available datasets from patients' primary tumors and normal retina have been compared with those found in WERI-Rb-1 cells to assess the relevance of DAC-driven genes as markers of primary retinoblastoma tumors. The effect of DAC treatment has been evaluated in vivo, both in subcutaneous xenografts and in orthotopic models. qPCR analysis of gene expression and Methylation-Specific PCR (MSP) was performed.

RESULTS

Our analysis of network maps for differentially expressed genes in primary tumors compared to DAC-driven genes identified 15 hub/driver genes that may play a pivotal role in the genesis and progression of retinoblastoma. DAC treatment induced significant tumor growth arrest in vivo in both subcutaneous and orthotopic xenograft retinoblastoma models. This was associated with changes in gene expression, either through the direct switching-on of epigenetically locked genes or through the indirect regulation of linked genes, suggesting the potential use of DAC as an epigenetic anti-cancer drug for the treatment of retinoblastoma patients.

CONCLUSION

There is a pressing need to develop innovative treatments for retinoblastoma. Our research revealed that DAC can effectively suppress the growth and progression of retinoblastoma in in vivo models, offering a potential new therapeutic approach to battle this destructive disease. This discovery highlights the impact of this epigenetic therapy in reprogramming tumor dynamics, and thus its potential to preserve both the vision and lives of affected children.

Health-related quality of life in children with childhood acute myeloid leukemia in China: A five-year prospective study

Purpose

This study aims to identify the key factors influencing health-related quality of life (HRQoL) of pediatric acute myeloid leukemia (AML) patients following their initial diagnosis and examine their impact on the five-year survival prognosis.

Methods

A chart review and follow-up were conducted for children with AML who participated in a prospective cohort study between 2017 and 2020. We identified factors influencing HRQoL through Pediatric Quality of Life Inventory™ (PedsQL™ 4.0), PedsQL™ Cancer Module 3.0 (CM 3.0) and PedsQL™ Family Impact Module 2.0 (FIM 2.0), as well as assessed the impact of impaired HRQoL on the overall outcomes of patients.

Results

Sixty-four subjects enrolled in the study had complete HRQoL outcome data, and 61 of them completed the 5-year follow-up. In CM 3.0, age was positively associated with parental proxy reports (p = 0.040), whereas divorced families were negatively associated with child self-reports (p = 0.045). A positive medical history correlates with FIM 2.0 (p = 0.025). Residence (p = 0.046), the occupation of caregivers (p = 0.014), disease severity (p = 0.024), and the only child (p = 0.029) exhibited statistically significant associations with the impairment of HRQoL. Impaired HRQoL scores shown by the PedsQL™4.0 parent proxy report (p = 0.013) and FIM 2.0 (p = 0.011) were associated with a reduced 5-year survival rate.

Conclusions

This study demonstrated that early impairment of HRQoL in pediatric acute myeloid leukemia patients has predictive value for long-term prognosis. Once validated, these findings may provide some guidance to clinicians treating children with AML.

Early Detection of Molecular Residual Disease and Risk Stratification for Children with Acute Myeloid Leukemia via Circulating Tumor DNA

PURPOSE

Patient-tailored minimal residual disease (MRD) monitoring based on circulating tumor DNA (ctDNA) sequencing of leukemia-specific mutations enables early detection of relapse for pre-emptive treatment, but its utilization in pediatric acute myelogenous leukemia (AML) is scarce. Thus, we aim to examine the role of ctDNA as a prognostic biomarker in monitoring response to the treatment of pediatric AML.

EXPERIMENTAL DESIGN

A prospective longitudinal study with 50 children with AML was launched, and sequential bone marrow (BM) and matched plasma samples were collected. The concordance of mutations by next-generation sequencing-based BM-DNA and ctDNA was evaluated. In addition, progression-free survival (PFS) and overall survival (OS) were estimated.

RESULTS

In 195 sample pairs from 50 patients, the concordance of leukemia-specific mutations between ctDNA and BM-DNA was 92.8%. Patients with undetectable ctDNA were linked to improved OS and PFS versus detectable ctDNA in the last sampling (both P < 0.001). Patients who cleared their ctDNA post three cycles of treatment had similar PFS compared with persistently negative ctDNA (P = 0.728). In addition, patients with >3 log reduction but without clearance in ctDNA were associated with an improved PFS as were patients with ctDNA clearance (P = 0.564).

CONCLUSIONS

Thus, ctDNA-based MRD monitoring appears to be a promising option to complement the overall assessment of pediatric patients with AML, wherein patients with continuous ctDNA negativity have the option for treatment de-escalation in subsequent therapy. Importantly, patients with >3 log reduction but without clearance in ctDNA may not require an aggressive treatment plan due to improved survival, but this needs further study to delineate.