ENPP2 and glioblastoma: There are other classes of molecules involved in glioblastoma invasion, such as secreted proteins such as the insulin-like growth-factor-binding protein family (IGFBPs), cysteine-rich 61/connective tissue growth factor/nephroblastoma overexpressed (CCN) family (Cyr61), angiopoietin 2 (Ang2), YKL40, and autotaxin (ATX)/lysophospholipase D. There are also membrane-type proteins, such as Fn14/TWEAK, EphB2/ephrin-B3, and CD155, associated with invasion.