Integrated germline and somatic molecular profiling to detect cancer predisposition has a high clinical impact in poor-prognosis paediatric cancer

Germline predisposition has a significant role in paediatric cancer. However, the optimal approach to identifying cancer-causing germline pathogenic variants (GPV) in children, and even the prevalence of GPV among children with cancer, remain unclear. Here we report our findings from a comprehensive survey of GPV in 496 children with poor-prognosis cancer. By integrating tumour and germline molecular profiling we identified GPV in 15.5% of patients, 48.1% of whom had not met clinical genetic testing criteria. Although the cancer type was outside the recognised phenotypic spectrum for 43.7% of reported GPV, 63.2% of these were clinically actionable for cancer risk. Integrated germline-tumour analysis increased the GPV detection rate by 8.5%, and informed germline interpretation in 14.3% of patients with GPV, highlighting the value of integrated analyses. Our findings establish the benefit of broad integrated tumour-germline screening, over phenotype-guided testing, to detect GPV in children with poor prognosis cancers.