FN1 and glioblastoma: The assays can easily be modified further according to specific requirements: migration/haptotaxis on different matrix proteins such as collagen, fibronectin, laminin, on endothelial cell monolayers, or (for glioblastomas) on recently described nanofiber scaffolds [15]: invasion into alternative matrixes (for example, collagen) or, to avoid animal tissue derivates, fully synthetic biopolymers; microenvironment-enriched spheroids incorporating endothelial cells, immune cells and/or stromal cells [10].