Alveolar RMS is commonly driven by the fusion of PAX3 or PAX7 to the FOXO1 gene (PAX3/7::FOXO1; ie, fusion-positive).2,3 In contrast, ERMS typically lacks the canonical PAX3/7::FOXO1 fusion (ie, fusion-negative); these tumors are typically driven by somatic mutations in the RAS signaling pathway,4,5 loss of heterozygosity at 11p15.5,6 and whole chromosomal alterations.7 This evidence concerns the gene PAX3 and embryonal rhabdomyosarcoma.