CREB1 and neoplasm: Typically, cAMP regulatory element-binding protein (CREB1) is overexpressed in a series of human neoplasms, and it can be activated through phosphorylation by a number of kinases, such as Akt (serine/threonine kinase 1), p90Rsk (ribosomal protein S6 kinase A1, RPS6KA1), protein kinase A (PKA), and calcium/calmodulin-dependent kinases.