CCK and prostate cancer: For instance, PKD1 has been involved in secretion of matrix metalloproteinase-2 and -9 from prostate cancer cells [61] or of insulin [62]; PKD2 was shown to regulate hypoxia-induced VEGF-A secretion from pancreatic tumor cells [63] or secretion of chromogranin A from neuroendocrine tumor cells [64]; and PKD3 promoted secretion of cholecystokinin-mediated pancreatic amylase [65].