In vitro secretion of transforming growth factor alpha (TGF-α): A comparison of the A431 cell line with three human oesophageal squamous cell carcinoma lines

Transforming growth factor alpha (TGF-α) is a single chain polypeptide which exists in a variety of forms differing in molecular weight. These forms are variously present in normal and neoplastic cells. Of particular interest are TGF-α's well-known mitogenic properties. The transition from a normal to a neoplastic cellular state results from signalling defects that may depend upon, iter alia, abonormal levels of expression and secretion of TGF-α. It is known that the secretion of TGF-α may be enhanced appreciably by agents such as phorbol 12-myristate 13-acetate (PMA), serum factors and epidermal growth factor (EGF). Here, we compare the efficacy of these three agents in the elevation of TGF-α secretion in the well studied A431 cell line with their previously undocumented efficacy in certain interesting, but little known, human oesophageal squamous cell carcinoma (SCC) lines.