Description
Amphiregulin (AR), also known as AREGB, is a glycosylated, heparin binding protein and member of the EGF family of cytokines (1). AR is an autocrine growth factor as well as a mitogen, for astrocytes, Schwann cells and fibroblasts. The soluble form of AR is released by proteolytic cleavage. AR binds to the same receptors as EGF and TGF-α, albeit with lower affinity, and can functionally replace EGF and TGF-α in murine keratinocytes (2). Its expression can be induced by phorbol ester, estrogen, androgen and other EGFR ligands (3). In vitro, AR inhibits the growth of various human carcinoma cell lines; contrastingly, the proliferation of some tumor cell, fibroblasts and normal cells is enhanced by AR (4-6). Overexpression of AR is reported in human cancers of breast, colon, stomach and pancreas, as well as in psoriatic epidermis