FGFR4 and cancer: Upon analysis with targeted RNA-Seq, we could assign 11 of 12 FN RMS cases to 3 genetically distinct groups: FN-RMS tumors with mutations in key signaling molecules (in the RAS signaling pathway and FGFR4), FN RMS tumors of the congenital and intraosseous SSRMS subtypes, and 3 FN RMS tumors with mutations in TP53 or DICER1, suggesting the possibility of an underlying cancer predisposition syndrome (confirmed in 2 patients).