FN1 and glioblastoma: Additionally, streak‐like arrangements of CD45+ cells were occasionally observed at tumor boundaries, such as in GBM01 and GBM11 (asterisks in Figure 5A), mirroring previous findings.[60] Taken together, our data suggest that in glioblastoma, CD45+ cell aggregates are closely associated with regions enriched in densely packed collagen I/III fibers and untensed fibronectin fibers.