MYOD1 is a master transcriptional regulator that drives skeletal muscle differentiation by activating muscle-specific gene expression 1. As a bHLH transcription factor, MYOD1 binds E-box motifs in regulatory regions and cooperates with other myogenic factors like MYF5 and MYOG to promote myoblast differentiation and myotube formation 2. MYOD1 exhibits pioneer factor activity, opening chr11 at closed regulatory regions to establish muscle cell identity 2. Beyond muscle development, MYOD1 functions as a tumor suppressor in several cancer types. In gastric cancer, MYOD1 suppresses cell migration and invasion by directly inhibiting FUT4 transcription, blocking glycan-mediated signaling pathways 3. In rhabdomyosarcoma (RMS), a pediatric muscle tumor, MYOD1 paradoxically promotes survival while preventing differentiation through interactions with the E3-ubiquitin ligase SKP2, which targets differentiation-promoting proteins p27 and p57 4. This MYOD1-SKP2 axis represents a critical oncogenic mechanism in fusion-negative RMS 4. MYOD1 mutations and expression profiling serve as emerging molecular biomarkers for RMS risk stratification and prognostication 5. Additionally, MYOD1 directly regulates CD276 expression in RMS, making it a potential immunotherapy target 6. Mutations in MYOD1 are associated with congenital myopathy 17, highlighting its essential role in normal muscle development.