CSPG4 and glioblastoma: Post-translational modifications of cell membrane-associated molecules, truncated membrane-bound or soluble fragments resulting from proteolytic cleavage, as well as the suggested presence of tumour cell-derived secreted PG NG2/CSPG4 molecules, may all serve different biological activities whose roles in glioblastoma vascularization and growth have still to be ascertained.