5530

TGF alpha

TGF-a was found in culture medium of fibroblasts transformed by some retroviruses in 1970s and nominated because of its ability to transform and induce the renal fibroblasts to proliferate. It is composed of 50 amino acid residues, with a 30% to 40% amino acid homology to epidermal growth factor (EGF), and binds the EGF receptor in the cellular membrane[20]. TGF-a was secreted by many transformed cells and involved in embryonic development. In human cancers, studies showed that TGF-a could serve as a tumor marker and as a marker for the malignant potential of a tumor[21]. Thus far, the types of carcinomas with which abnormal TGF-a expression has been associated include liver[22], gastrointestinal[23], breast[24], skin[25], lung[26], brain[27] and ovarian cancers[28]. TGF-a might play a role in the processes involved with tumor initiation and growth. In cell lines, TGF-a has been found to be associated with autocrine and/or paracrine types of cellular growth initiation and with increased levels of oncogene expression[29,30]. It could promote the hepatocellular proliferation, differentiation, regeneration and tumor cell growth[31]. Transgenic mice that overexpressed TGF-a developed liver tumors between 12 and 15 months of age[22].

Cite:

ZHANG J, WANG WL, LI Q, & QIAO Q. (2004). Expression of transforming growth factor-alpha and hepatitis B surface antigen in human hepatocellular carcinoma tissues and its significance. World Journal of Gastroenterology : WJG. 10, 830-3.

2. TRANSFORMINGGROWTH FACTOR-~ (TGF-a)isa 5,600 mol wt, 50-amino acid polypeptide that shares 35% sequence homology (including all six cysteines), a cell surface membrane receptor [TGF-cu-epidermal growth factor receptor (EGFr)], and biological activity with EGF (16, 29, 30). TGF-ar was originally identified as a protein that reversibly induced anchorage-independent growth of several nontransformed cell lines (45) and was considered...