Epidermal growth factor （EGF） is a small growth factor containing 53 amino acid residues that promotes the
proliferation of mesenchymal and epidermal cells. Mature proteins, much smaller than 53aa, are produced by protein
hydrolysis in the proximal EGF domain across the membrane. EGF is well preserved in mammals, and the EGF in mature
humans is 70% the same as that in mice and mice. EGF and fibroblast growth factor 2 （fgf-2） induce the proliferation of neural
precursor cells isolated from specific parts of the embryonic and adult brain. EGF and somatopodin c supplemental medium
were substituted for 5% thrombocytopenic anemia plasma （PPP） and had the ability to inhibit BALB/C-3T3 cell density. The
biological activities of EGF include epithelium formation, angiogenesis, inhibition of gastric acid secretion, proliferation of
fibroblasts, and colony formation of epidermal cells in culture.