KNG1 and cancer: It can trigger arteriolar dilation, enlarge the endothelial gaps and enhance vascular permeability by stimulating the release of nitric oxide, prostacyclin, and endothelium-derived hyperpolarizing factor (EDHF).70 Maeda et al.71,72 first demonstrated the presence of BK in blood plasma, peritoneal effusion, and pleural fluids of cancer patients, and showed that BK plays an essential role in the EPR effect.