In addition, tenascin-C induced the increased expression of the active form of MMP-2 in GBM cells and brain-derived cells, which might contribute to the continuous production of PDGF, thus suggesting that a positive spiral loop of tenascin-C/TNIIIA2/PDGF signaling leads to hyper-proliferation of GBM cells. Here, TNC is linked to glioblastoma.