Keyword: NGS

ABSTRACT: Introduction: Despite the relatively low mutational burden of most pediatric tumors, molecular genetic studies are increasingly being used in pediatric oncology. They enable confirmation of diagnosis, assessment of prognosis, and identification of potential targets for molecularly targeted therapy. Analysis of molecular diagnostic results in real-world clinical practice allows us to assess the capabilities and limitations of molecular diagnostics across different pediatric tumors.
Materials and Methods: Targeted sequencing of tumor DNA using a customized QIAseq panel (Qiagen, Germany) was performed in 334 patients with extracranial solid tumors treated at the Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology and Immunology between 2018 and 2023.
Results: The highest diagnostic yield was observed in malignant rhabdoid tumors (n=23): diagnostically significant alterations were identified in 91.3% of patients.
In most cases, these alterations were highly specific to this tumor type and could be used to confirm the diagnosis alongside morphological and immunohistochemical data.
Prognostically significant molecular alterations were most frequently detected in neuroblastoma – in 66.7% of patients (112/168). The majority of these consisted of mutations in genes of the RAS/p53 signaling pathways, allowing further characterization of tumor biology and identification of patients with molecular features potentially associated with disease course and response to therapy.
Potentially therapeutically significant alterations were identified in 36% of patients (120/334). However, the presence of a molecular target did not always lead to the administration of the corresponding drug, as evidence for the efficacy of targeted therapy in children remains limited for a significant proportion of these alterations.
Targeted therapy based on molecular genetic testing results was administered in 6.3% of cases (21/334), predominantly in neuroblastoma (n=13).
It was used in the first-line setting or at first relapse in 66.7% of cases (14/21). In 61.9% (13/21) of patients, targeted agents were used in combination with standard antitumor therapy.
An objective response or disease stabilization lasting more than 6 months was observed in 66.7% (14/21) of patients. The median time to best response or stabilization was 6 months (range 0.8–12.3). The median duration of targeted therapy as monotherapy was 10.9 months (range 0.8–43.5), and in combination with chemotherapy – 12.3 months (range 0.3–61.5). In 42.8% (9/21) of patients, the response was maintained at the time of last follow-up.
Conclusion: Thus, molecular genetic plays an important role in improving the diagnosis and treatment of pediatric tumors. Futher accumulation of clinical and molecular data will provide a deeper understanding of tumor biology and expand opportunities of personalized treatment.

ABSTRACT: Minimal residual disease (MRD) has become a significant predictor of relapse and survival in acute myeloid leukemia (AML), indicating the extent of remission beyond traditional morphological evaluation. Although multicolor flow cytometry and quantitative PCR are essential methodologies in minimal residual disease identification, both are constrained by immunophenotypic variability, the necessity for stable molecular targets, and limited sensitivity. Advancements in next-generation sequencing (NGS) have revolutionized the minimal residual disease (MRD) field by enabling highly sensitive, mutation-driven identification of leukemic clones across a broad genomic landscape. Contemporary error-suppressed next-generation sequencing techniques—such as unique molecular identifiers, duplex sequencing, and single-molecule molecular inversion probes—have enhanced analytical sensitivity to the 10⁻⁵ to 10⁻⁶ range, enabling the detection of ultra-low-frequency variations with greater specificity. These techniques improve clinical risk classification, refine prognostication within genetically defined AML subtypes, and guide therapeutic options, including post-remission therapy, targeted inhibition, and the timing and intensity of allogeneic stem cell transplantation. Innovative applications, such as single-cell sequencing, cell-free DNA studies, and integrative multi-omic MRD evaluation, enhance the capabilities of genomics-based monitoring. Nonetheless, obstacles remain, such as differentiating cancer mutations from clonal hematopoiesis, standardizing analytical pipelines, establishing clinically relevant thresholds, and incorporating NGS MRD into standardized treatment protocols. This review encapsulates contemporary NGS methods for AML MRD diagnosis, assesses their clinical ramifications and constraints, and suggests future pathways necessary for comprehensive clinical integration. With advancements in the area, NGS-based MRD is set to become a pivotal element of precision-guided AML control.