Cross-Omic Insights into Relapse and Refractory Mechanisms in Pediatric T-ALL

Poster Abstract: Kamila Szumala1, Monika Drobna-Śledzinska2, Maria Kosmalska2, Małgorzata Dawidowska2, Roman Jaksik1

Abstract

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematologic malignancy 
characterized by extensive genetic heterogeneity. Despite major advances in medicine towards 
personalized therapies, a significant subgroup of patients still experience relapse or treatment 
resistant disease, which is associated with poor prognosis. The aim of this project is to identify 
molecular signatures of relapse and/or treatment refractoriness across multiple omic layers and 
to develop a multi-omic predictive model for these events.


The study cohort comprised 62 pediatric patients diagnosed with T-ALL, for whom whole-genome 
sequencing (WGS), RNA-seq, miRNA-seq and DNA methylation profiling were available. Patients 
were clinically annotated by experts according to three outcome categories: relapse occurrence, 
treatment refractoriness, and the presence of either event. Each omic dataset underwent 
standard preprocessing, including quality control and removal of invariant features. For WGS and 
RNA-seq data, multiple aggregation strategies were applied to derive biologically meaningful 
feature representations. Feature selection was performed using the Boruta algorithm, and 
classification models were constructed with a Random Forest approach to identify predictive 
molecular patterns associated with relapse and refractoriness. Before classification, 
downsampling was applied to balance class sizes, and the entire procedure was executed within 
a LOOCV loop.

Conclusions: The developed multi-omic classifiers achieved a balanced accuracy of approximately 0.8 across 
all labeling schemes. RNA-seq features had the greatest impact, despite the limited performance 
of this omic layer in independent modeling. Integrative models revealed heterogeneous but 
complementary molecular patterns across omic layers, suggesting interrelated regulatory 
mechanisms and highlighting the substantial molecular diversity underlying T-ALL relapse and 
refractoriness. 
The study was funded by the National Science Centre Poland, 2022/47/B/NZ5/00663