EPIDERMAL GROWTH FACTOR

Epidermal Growth Factor



Epidermal Growth Factor

Epidermal Growth Factor and Its Role

The epidermal growth factor (EGF) is a hormone protein with multiple actions, primarily trophic. Its site of action is not just the fabric epidermal but to all the tissue. The binding of the hormone on EGFR activity causes mitotic very fast in the target tissue.

EGFR is expressed on the surface of both normal and transformed epithelial cells and is involved in regulation of cell growth and differentiation. Like all receptor tyrosine kinases, EGFR consists of three parts: an extracellular ligand-binding domain, a transmembrane hydrophobic region and an intracellular tyrosine kinase domain.

The receptor activation of epidermal growth factor receptor (EGFR) involves a co genesis by promoting cell proliferation, cell motility, angiogenesis and inhibiting apoptosis. This activation can be induced by various abnormalities including increased expression of certain ligands. Although there is no standardized technique for evaluation and most studies display that the level of expression of EGFR is a prognostic factor for certain tumors. It is thus a poor prognosis that could influence the therapeutic orientations in squamous carcinoma of the head and neck cancers in the cervix, esophagus, bladder and ovarian cancers. Conversely, its prognostic value is not important in lung cancer. The non-small cell remains to be demonstrated for a large majority of adenocarcinomas such as breast and colorectal cancers. Considering its role in oncogenesis and its prognostic value, the EGFR in the future could be a therapeutic target of choice for targeted therapies.

Currently, a vast number of basic researches have been focusing on finding new rational approaches to cancer therapies. Understanding the molecular mechanisms responsible for the mitogenic activity of transformed cells may open up the new ways to control the tumor growth. One of the objects studied actively in recent years as a new anticancer target is the epidermal growth factor receptor (EGFR).

Thus, the following basic mechanisms of activation of EGFR depend on signaling pathways in tumor cells:

1) Over expression of EGFR

2) Excessive production of growth factors (TGF-a, EGF)

3) The mutation of EGFR and, consequently, its increased activity in the absence of growth factors

4) Geterodimerizatsiya receptor

In a number of tumors of epithelial nature (lung cancer, ovarian, colon, prostate, squamous cell carcinoma of head and neck), detects tshe over expression of EGFR and / or one of its ligands (EGF; TGF-a), which can cause increased proliferative activity of the transformed cells. Over expression of EGFR in tumor cells are commonly associated with advanced and metastatic phenotype of the disease and; therefore, correlates with poor prognosis (Ullrich 2002, pp. 5).

Structure of Epidermal Growth Factor

The growth factor receptor (EGFR or ErbB-1) belongs to a family of receptor tyrosine kinase which also includes receptors ErbB-2, ErbB-3 and ErbB-4. Over expression of EGFR, which occurs in a variety of epithelial tumors is associated with poor clinical prognosis in cancers of the colon, breast and lung. The group is to identify the phenotypic and genotypic profiles that make ...