Swine Stem Cell Factor (SCF) (also known as KIT ligand, KITLG, mast cell growth factor, or steel factor) is a cytokine and growth factor that plays an important role in hematopoiesis, stem cell maintenance, and immune cell development in pigs (Sus scrofa domesticus). SCF belongs to a group of hematopoietic growth factors that regulate the survival, proliferation, and differentiation of stem and progenitor cells. It functions by binding to the c-Kit receptor (CD117), a receptor tyrosine kinase expressed on hematopoietic stem cells, mast cells, melanocytes, and germ cells, activating intracellular signaling pathways including PI3K/AKT, MAPK, and JAK/STAT that promote cell survival, proliferation, and differentiation. In pigs, SCF is produced by bone marrow stromal cells, fibroblasts, endothelial cells, and epithelial cells, and exists in both membrane-bound and soluble forms, allowing both localized and systemic regulation of c-Kit–expressing cells. Swine SCF is important for maintenance of hematopoietic stem cells within the bone marrow niche, as well as for mast cell development, pigmentation biology, and germ cell survival. Because pigs are widely used as large-animal models for human hematopoiesis, immunology, and regenerative medicine, characterization of swine SCF supports studies of stem cell regulation, immune cell development, and c-Kit–mediated signaling pathways relevant to both livestock health and translational biomedical research.