Canine, Equine, Feline, Ferret, Mink, and Swine Transforming Growth Factor Alpha (TGF-α) is a member of the epidermal growth factor (EGF) family of growth factors, which also includes epidermal growth factor (EGF), amphiregulin, betacellulin, epiregulin, and heparin-binding EGF-like growth factor (HB-EGF). In dogs (Canis lupus familiaris), horses (Equus caballus), cats (Felis catus), ferrets (Mustela putorius furo), mink (Neovison vison), and pigs (Sus scrofa), the mature TGF-α protein is identical at the amino acid level, indicating strong evolutionary conservation and suggesting highly similar biological functions across these mammalian species. TGF-α is synthesized as a membrane-bound precursor (pro–TGF-α) that is cleaved to release a soluble ligand capable of binding the epidermal growth factor receptor (EGFR/ErbB1). Activation of EGFR triggers intracellular signaling pathways including MAPK/ERK, PI3K/AKT, and JAK/STAT, which regulate cell proliferation, epithelial growth, differentiation, and tissue repair. In these species, TGF-α is expressed in tissues such as the skin, gastrointestinal tract, respiratory epithelium, mammary gland, and reproductive tissues, where it contributes to epithelial development, wound healing, and tissue regeneration. Dysregulated EGFR signaling involving TGF-α may also contribute to fibrotic processes and tumor development in epithelial and glandular tissues. Because several of these species serve as important veterinary patients and comparative biomedical models, characterization of TGF-α supports research on EGFR signaling, epithelial biology, tissue regeneration, and cancer biology relevant to both animal health and translational medicine.