Amphiregulin(AREG), also known as colorectum cell-derived growth factor, CRDGF, SDGF and AREG, is a member of the epidermal growth factor family and the amphiregulin family. Members of EGF family are cytokines that include 10 proteins such as EGF, TGFb, HBEGF, and the various heregulins. Amphiregulin is a single-pass membrane protein and contains one EGF-like domain. It plays a key role in epithelial development in various organs. Amphiregulin has a realationship with epidermal growth factor (EGF) and transforming growth factor alpha (TGF-alpha). It is an autocrine growth factor as well as a mitogen for astrocytes, Schwann cells, and fibroblasts. As a bifunctional growth-modulating glycoprotein, amphiregulin inhibits growth of several human carcinoma cells in culture and stimulates proliferation of human fibroblasts and certain other tumor cells. Amphiregulin also may play a protective role in bleomycin-induced pneumopathy, probably through the activation of survival signals.