Several studies show that GBM cells over-express the Cl− channels ClC-3 and the Ca2+-activated K+ channels KCa1.1 and KCa3.1, and their coordinated activity, promoting K+ and Cl− transmembrane fluxes, supports cell volume and membrane potential changes necessary for GBM cell migration and invasion (Catacuzzeno et al., 2012; Turner and Sontheimer, 2014). Here, KCNN4 is linked to glioblastoma.