In another study, Cai et al. [11] discovered that Slit2/Robo4 inhibited glioma-induced EC proliferation, migration and tube formation, and that ECs of the Robo4 (-) + protein kinase B (AKT) inhibitor LY294002 group cultured with glioma-conditioned medium showed decreased cell viability, cell proliferation and tube formation compared with cells in the Robo4 (-) group. Here, ROBO4 is linked to central nervous system cancer.