PDPN and glioblastoma: There is a newly discovered surface receptor on platelets, C-type lectin-like receptor 2 (CLEC-2), that is activated by the mucin-type sialoglycoprotein podoplanin (aggrus), which is a known platelet aggregation-inducing factor present on multiple tumor cells (squamous cell carcinoma, mesothelioma, glioblastoma, sarcoma) and lymphatic endothelial cells [230–232].