MMP2 and glioblastoma: GelMA contains MMP‐degradable sites to facilitate cell migration via matrix degradation, and prior studies from our lab have established that GBM cells express MMP2 and MMP9 when cultured in GelMA (with or without the inclusion of vascular cells).[13, 36] In contrast to other reports,[24, 37] the presence of endothelial cells alone was not sufficient to increase invasion.