Description
Epiregulin (also known as EREG) is a member of the EGF family of growth factors. It binds specifically to EGFR (ErbB1) and ErbB4 but not ErbB2 or ErbB3 (1). It is expressed mainly in the placenta and peripheral blood leukocytes, as well as certain carcinomas of the bladder, lung, kidney and colon (2). EREG has been shown to act as an autocrine growth factor for human keratinocytes, stimulating the proliferation human keratinocytes under both subconfluent and confluent culture conditions in the absence of exogenous EGF family growth factors. In keratinocytes EREG upregulates the mRNA levels of HB-EGF, amphiregulin, and TGF-alpha. It has been shown that EGF, HB-EGF, amphiregulin, and TGF-alpha increase EREG mRNA levels (3). EREG inhibits the growth of several epithelial tumor cells and stimulates the growth of fibroblasts and various other types of cells. It binds to the EGF receptors of epidermoid carcinoma A431 cells much more weakly than EGF, but is much more potent than EGF as a mitogen for rat primary hepatocytes and Balb/c 3T3 A31 fibroblasts (4). EREG has been implicated in the implantation process during pregnancy (5)