ABSTRACT
This chapter describes the role of an extracellular matrix substance (ECM), tenascin, in cancer development. The molecular composition of the ECM is presumably different in each site, and the mechanism by which molecules express the specific information remains unclear. Biochemical studies of human glioma U-251MG tenascin revealed that the mass of native protein is 1900 kDa, while that of chicken tenascin is 1200 kDa, as determined by agarose gel electrophoresis in sodium dodecyl sulfate and by sedimentation equilibrium. Many ECM proteins contain a short amino acid RGD in their sequence, which interacts with the cell surface integrins. Tenascin contains epidermal growth factor (EGF) -related domains, so the EGF receptor could be a possible tenascin receptor. During development of the mammary gland by ductal elongation with branching, tenascin disappears from the dense mesenchyme, remaining in the nipple sheath mesenchyme. In malignant tumors it is likely that both stroma cells and cancer cells can express tenascin at the same time.
