141P Comprehensive genomic profiling-based precision oncology in the management of rare paediatric soft tissue sarcomas

Soft tissue sarcomas are a heterogeneous group of malignant tumours, accounting for the fifth most common paediatric cancer. Next-generation sequencing-based (NGS) comprehensive genomic profiling (CGP) soft tumours associated with poor prognosis can identify actionable biomarkers and determine prognostic therapeutic stratification patient management. Diagnostic samples 20 patients diagnosed various were investigated using CGP assay (Illumina TruSight Oncology 500). The identified single nucleotide variants, small insertions or deletions, copy number alterations, gene fusions, microsatellite stability status, tumour mutation burden analysed. Using Clinical insight (Qiagen) PierianDx (Pierian) software, variants determined. Our study revealed potentially alterations intervention in 75% cases (15/20). Novel detected several entities which have not previously been published. All characterised by low burden, none instability. targetable fusions included three NTRK TFG-ROS1, ROS1-GIT2 EML4-ALK fusions. frequent affected CDK4, ALK FGFR1 genes, 28.6% (4/20), 14.3% (2/14) cases, respectively. Single 7 including ALK, CHEK2, ESR1, FANCL, MET, NBN NRAS, across six cases. Based on NGS results, targeted therapy was prescribed 5 (tazemetostat epithelioid sarcoma, entrectinib inflammatory myofibroblastic infantile fibrosarcoma, larotrectinib angiosarcoma fibrosarcoma). At least partial remission achieved all receiving therapies. In our study, routine application TSO500 CPG led to administration therapies 25% at clinical response this cohort.