Expanding the utility of transcriptome analysis for mutation detection in high-risk childhood precision oncology

In precision oncology, rapid and comprehensive mutation detection is essential for diagnosis, prognosis and treatment. Whole transcriptome sequencing (RNA-seq) offers unique advantages by capturing functional consequences of genomic alterations and has the potential to detect not only oncogenic fusions, but also a broad spectrum of clinically relevant mutations traditionally identified from DNA-based approaches. We evaluated the utility of RNA-seq in a cohort of 477 high-risk paediatric tumours enrolled in the ZERO childhood cancer precision medicine programme with matched WGS data. A combination of reference-guided and reference-free RNA-seq algorithms were used to detect and interpret fusions and intragenic structural variants (SVs), resolving events from complex rearrangements and paralogous loci. RNA-seq detected 95% of gene fusions, including 33 missed by WGS. All intragenic SVs (100%) detected by WGS were also identified by RNA-seq and RNA-seq was essential for identification and/or interpretation of 30% of SVs. Additional functional insight such as aberrant splice-junctions and transcript abundance were critical for resolving pathogenicity. For single nucleotide variants and small insertions/deletions (SNVs/Indels), RNA-seq confirmed 92% and was essential for refining pathogenicity in 22% through allele-specific expression and splice assessment. These findings highlight RNA-seq as a critical complement to WGS, that transforms interpretation by adding functional context, thereby elevating diagnostic confidence and clinical decision-making.

• Type: Other
• Archive: European Genome-phenome Archive (EGA)