Enhanced Detection of Splice-Altering Variants in Hematologic Malignancies Using Targeted RNA-Sequencing Data

RNA-based targeted sequencing aids the detection of several types of variants in hematologic and other malignancies, including splice-altering variants. However, accurately identifying clinically relevant mis-splicing events remains challenging because of the inherent complexity of the human transcriptome and the high prevalence of false-positive splice junctions in deep RNA-sequencing data. To address these challenges, SpliceChaser and BreakChaser were developed, which are bioinformatics tools designed to enhance the detection and characterization of relevant splice-altering events. SpliceChaser improves the identification of clinically relevant atypical splicing by analyzing read length diversity within flanking sequences of the mapped reads around the splice junctions. BreakChaser processes soft-clipped sequences and alignment anomalies to enhance the detection of targeted deletion breakpoints associated with atypical splice isoforms generated from intrachromosomal gene deletions. These tools were developed and validated using a cohort of >1400 RNA-sequencing samples from patients with chronic myeloid leukemia. Collectively, SpliceChaser and BreakChaser achieved a positive percentage agreement of 98% and a positive predictive value of 91% for the detection of clinically relevant atypical splice-altering variants or gene deletions in the targeted regions. By integrating splicing and breakpoint detection with robust filtering strategies, these tools facilitate precise identification of clinically relevant variants, paving the way for improved diagnostics and therapeutic strategies in chronic myeloid leukemia and other malignancies.