Glypicans are a family of HSPGs that are attached to the cell membrane by a glycosyl-phosphatidylinositol anchor. Glypicans are considered to have the ability to modulate the activities of HBGFs. The expression of glypicans is regulated temporally and spatially during development, suggesting they are involved in development and morphogenesis. To date, six glypicans (Glypican 1 to Glypican 6) have been identified in mammals. Glypican 1 (GPC1) is most ubiquitously expressed in adult tissues. GPC1 promotes efficient signaling by HBGFs and plays a critical role in cell growth and differentiation. GPC1 is involved in tumorigenesis and angiogenesis, and is frequently overexpressed in several types of tumors including pancreatic carcinoma, breast cancer and glioma.
