TWIST1 is a basic helix-loop-helix transcription factor that functions as a critical regulator of developmental and pathological processes. As a transcriptional regulator, TWIST1 inhibits myogenesis through interactions with E proteins and MYOD1, while also repressing pro-inflammatory cytokines 1. TWIST1 regulates gene expression through homodimer and heterodimer formation with differential outcomes: homodimers induce FGFR2 and POSTN expression, while heterodimers repress these genes and induce THBS1 expression. Beyond development, TWIST1 drives pathological fibrosis in multiple organs. In kidney fibrosis, TWIST1 expression increases in myofibroblasts following TGF-β1 stimulation and promotes fibroblast activation via downstream Prrx1 and TNC signaling; fibroblast-specific TWIST1 deletion reduces fibrosis in injury models 2. Similarly, in Crohn's disease intestinal fibrosis, TWIST1 highly expressed in FAP+ fibroblasts mediates ECM production, and TWIST1 inhibition ameliorates fibrosis 3. In cancer, TWIST1 promotes triple-negative breast cancer aggressiveness through epithelial-mesenchymal transition and cancer stem cell functions; its stability is regulated by the CDK1-USP29 deubiquitination axis 4. TWIST1 also contributes to atherosclerosis through GATA4-mediated transcriptional mechanisms that promote endothelial dysfunction and inflammation at disturbed flow sites 5. Additionally, TWIST1-TSG6 expression ratios predict mesenchymal stem cell potency and immunomodulatory capacity 6.