| Scientific Background: | Fibronectins are high molecular weight, disulphide-linked, dimeric cell adhesion glycoproteins found in basement membranes and in the interstitial connective tissue matrix. A single fibronectin gene is subject to alternative splicing in a cell-type-, development- and age-regulated manner which gives rise to multiple molecular forms. In addition to their prominent role in adhesion, fibronectins have been reported to mediate various aspects of cellular interaction, including migration during development and wound-healing, haemostasis, and the regulation of cell growth and differentiation. Cellular fibronectins (cFn) are found in low amounts in normal human plasma and tissues, but they are abundant in the plasma of carcinoma patients and in the stroma of various carcinomas. In contrast, a soluble form of fibronectin produced by hepatocytes is readily detectable in plasma and becomes deposited in pericellular matrices and within tissues. This form of fibronectin, referred to as ‘plasma fibronectin’ (pFn), differs from cFn by the absence of an amino acid sequence, known as extra domain A1. |
