PAK4 and glioblastoma: Fu et al. (2020) also found that endothelial deletion of Zeb1 leads to improved vascular normalization and reduced cancer progression in various tumor models by reducing tumor vessel density and permeability, mainly by reducing TGF-β signaling in ECs and associated tumor stroma. More recently, Ma W. et al. (2020) found that PAK4 drives mesenchymal gene expression in the EC of glioblastoma blood vessels, and that in this setting, Zeb1 (but not Slug) is required for PAK4 suppression of cellular adhesion proteins leading to increased vascular permeability.