cAMP response element-binding protein (CREB) and CREB-regulated transcription co-activator (CRTC) affect cell proliferation, differentiation, metabolism, and other biological processes.67 Increased CREB activity confers to tumor progression, chemotherapy resistance, and reduced survival.68 CREB is another well-established SIK downstream effector. This evidence concerns the gene CREB1 and neoplasm.