TWIST2 is a basic helix-loop-helix (bHLH) transcription factor that functions as a molecular switch regulating gene expression in mesenchymal cell lineages 1. The protein binds to E-box DNA sequences and can either activate or repress target genes through direct DNA binding and recruitment of coactivators or repressors, as well as through protein-protein interactions 2. TWIST2 plays critical roles in multiple developmental processes, including negative regulation of osteoblast differentiation and myogenesis 1. In fusion-negative rhabdomyosarcoma, TWIST2 blocks muscle differentiation by inhibiting MYOD activity and controls H3K27 acetylation at distal enhancers through interactions with chr2 remodelers SMARCA4 and CHD3 3. The protein is also involved in regulating inflammatory responses and energy metabolism 1. Disease-wise, TWIST2 mutations cause Setleis syndrome, with loss-of-function mutations leading to upregulation of genes like CHR2 through disrupted competition with transcription factors such as ADD1/SREBP1c 4. TWIST2-expressing cells have been identified in human skeletal muscle, where they increase with aging and resistance exercise training 5. Additionally, TWIST2 contributes to chemoresistance in lung adenocarcinoma through HDAC4 super-enhancer-mediated regulation 6.