No abstract

Despite gains in survival, outcomes for patients with metastatic or recurrent rhabdomyosarcoma (RMS) remain dismal. In a collaboration between the National Cancer Institute, Children's Oncology Group, and Broad Institute, we performed whole-genome, whole-exome and transcriptome sequencing to characterize the landscape of somatic alterations in 147 tumor/normal pairs. Two genotypes are evident in RMS tumors; those characterized by the PAX3 or PAX7 fusion and those that lack these fusions but harbor mutations in key signaling pathways. The overall burden of somatic mutations in RMS is relatively low, especially in tumors that harbor a PAX3/7 gene fusion. In addition to previously reported mutations of NRAS, KRAS, HRAS, FGFR4, PIK3CA, CTNNB1, we found novel recurrent mutations in FBXW7, and BCOR providing potential new avenues for therapeutic intervention. Furthermore, alteration of the receptor tyrosine kinase/RAS/PIK3CA axis affects 93% of cases providing a framework for genomics directed therapies that might improve outcomes for RMS patients.