Description_x000D_ Biochem/physiol Actions_x000D_ Also known as keratinocyte autocrine factor (KAF); expression of amphiregulin mRNA has been found in numerous carcinoma cell lines and epithelial cells of several human tissues including colon, stomach, breast, ovary, and kidney._x000D_ Components_x000D_ Human amphiregulin is produced by a DNA sequence that encodes a 98 amino acid residue form of mature human amphiregulin. This corresponds to amino acid residues 101-198 in E. coli. Amphiregulin is a glycoprotein produced in response to treatment of the cell line MCF-7, a human breast carcinoma cell line, with PMA, a protein kinase C activator and potent tumor promoter._x000D_ Caution_x000D_ This product should be stored at -20°C. After preparation, the product can be stored at 2-8°C for one month, or frozen in aliquots at -20°C or -70°C for more extended storage._x000D_ Physical form_x000D_ Lyophilized from a 0.2 μm filtered solution in PBS, pH 7.4 with 50 μg BSA per 1 μg as a carrier protein._x000D_ Preparation Note_x000D_ It should be reconstituted by adding sterile PBS containing 0.1% HAS or BSA to a concentration greater than 10 μg/mL._x000D_ Analysis Note_x000D_ Measured in a cell proliferation assay using Balb/3T3 mouse embryonic fibroblast cells. Marquardt, H. et al. (1984) Science 223:1079. The ED50 for this effect is typically 5-15 ng/mL.