CREB1 and neoplasm: Dopamine secretion is locally increased due to an imbalance in dopamine metabolism, including activation of dopa decarboxylase and a decrease in monoamine oxidase A. Dopamine promoted proliferation and metastasis against the background of high D1R expression in tumor cells via the cAMP/PI3K/AKT/CREB regulatory pathway, while downregulation of D1R had opposite effects.