It has been investigated over recent decades that the molecular mechanisms involved in the development and uncontrolled proliferation of cancers involve abnormalities of oncogenes and growth factor-receptor systems. Epidermal growth factor(EGF) is a single-chain polypeptide(MW 6045) that was first isolated from the mouse submaxillary gland by Cohen in 1962. It is known that the epidermal growth factor-stimulated growth regulatory system is involved in cellular proliferation, both normal and neoplastic(Cowley et al., 1986 ; Ozanne et al., 1986 ; Stoscheck et al., 1986 ; Fixher et al., 1990). In order for EGF to interact with the cell, a specific receptor located at the cell surface is required. Epidermal growth factor receptor(EGFR) is a 170 KDa membrane-bound glycoprotein encoded for by the c-erbB-1 oncogene. It was first purified from the A431 cellline which was derived from the epidermoid carcinoma of the vulva(Cohen, 1983 ; Carpenter et al., 1986 ; Carpenter et al., 1987 ; Yarden et al., 1988). EGFR is a member of growth factor receptor family of protein tyrosine kinases, a class of cell cycli regulatory molecules. The receptor is capable of binding several ligands such as EGF, transforming growth factor(TGF)a(Fisher et al., 1990), amphiregulin(Shoyab et al.,1989), and heparin-binding EGF(Higashiyama et al., 1991). It is activated when its ligand binds to the extracellular domain, resulting in autophosphorylation of the receptor`s intracellular tyrosine kinase domain(Cohen et al., 1980 ; Schreiber et al., 1983). Dimerization, conformational changes ans internalization of EGFR function to transmit intracellular signals leading to regulation of cell growth(Carpenter and Cohen, 1979).