PAX3 and alveolar rhabdomyosarcoma: This section focuses on three distinct, but interconnected, mechanisms of transcriptional repression that contribute to ARMS pathogenesis: (1) PAX3-FOXO1–mediated silencing of ACTA1 via the RhoA–MKL1–SRF pathway, (2) TBX2-driven repression of muscle-specific gene expression, and (3) MYOG inactivation and its exploitation in targeted gene therapy.