Circulating Tumor DNA in Intermediate Risk Rhabdomyosarcoma

In this study, we evaluated circulating tumor DNA (ctDNA) as a biomarker in the serum of 124 patients with newly diagnosed intermediate risk rhabdomyosarcoma (IR RMS) from the Children's Oncology Group (COG) biorepository. In addition to pre-treatment serum, we also analyzed matched tumor tissue and germline in a subset of patients. We profiled samples using ultra-low passage whole genome sequencing (ULP-WGS) and a new custom hybrid-capture sequencing assay, Rhabdo-Seq, to detect copy number alterations, rearrangements, and single nucleotide variants. We found that patients with detectable ctDNA at diagnosis had significantly worse outcomes than those without detectable levels of ctDNA. Our study demonstrates that baseline ctDNA detection is feasible and prognostic in IR RMS. The ULP-WGS and targeted next-generation sequencing (Rhabdo-Seq and TranSS-Seq) data are available in this study.