The PODXL content of carcinoma cell EVs must be within a certain range for them to encourage fibroblasts to deposit pro-migratory ECM, and expression of mutant p53 functions to move EV PODXL levels into this range.5 To determine whether PODXL levels in EVs from GBM is causally linked to their ability to alter ECM deposition by astrocytes, we generated E2 cells in which PODXL levels were either increased (by overexpression) or reduced (using CRISPR). Here, PODXL is linked to carcinoma.