HSPG2 and neoplasm: Heparan sulphate, and HSPGs (syndecan, perlecan, and glypicans) cell–matrix interactions mediate endocytosis via caveolin-mediated pathways or lipid raft-mediated pathways.112 Small GTPases, such as Cdc42, Rac1, RhoA, RhoG, and ARF6 as well as actin also regulate HSPG internalisation.113,114 HSPG serves as a receptor for APRIL, a proliferation-inducing ligand, which is a member of the tumour necrosis factor (TNF) family, to promote cell proliferation and tumour growth.115 Very-low density lipoprotein (VLDL) binding and internalisation is dependent on complexing with cell-surface HSPGs.