KCNJ11 and brain neoplasm: Importantly, activation of Ca2+-activated BKCa K+ channels (encoded by the KCNMA1 gene) [73,74] and ATP-sensitive Kir6.2 (encoded by the KCNJ11 gene) K+ channels [75] in brain endothelial and brain tumor cells has been demonstrated in animal models to increase the permeability of the BBTB.