Glypican-5 (GPC5), is a cell membrane protein which belongs to the glypican family. The glypicans compose a family of glycosylphosphatidylinositol-anchored heparan sulfate proteoglycans that may play a role in the control of cell division and growth regulation. So far, six members (Glypican-1/GPC1, Glypican-2/GPC2, Glypican-3/GPC3, Glypican-4/GPC4, Glypican-5/GPC5, Glypican-6/GPC6) of this family are known in vertebrates. In adult, Glypican-5 is primarily expressed in the brain. It is also detected in fetal brain, lung and liver. Glypican-5 enhances the intracellular signaling of FGF2 and HGF. It alters the cellular distribution of FGF2. The properties of Glypican-5 make it an attractive target for therapeutic intervention in rhabdomyosarcomas and other tumors that amplify and/or overexpress its gene. Glypican-5 is over-expressed in lymphoma cell lines that had shown amplification. It is a likely target for amplification, and that over-expression of GPC5 may contribute to development and/or progression of lymphomas and other tumors.