cAMP-specific 3',5'-cyclic phosphodiesterase 4A (PDE4A) is an enzyme that in humans is encoded by the PDE4A gene. It belongs to the PDE family who hydrolyze 3′-5′-cyclic adenosine monophosphate (cyclic AMP) to 5′-adenosine monophosphate (AMP). PDE enzyme family plays a pivotal role in regulating levels of the second messenger cAMP. Consequently, PDE4 inhibitors have been investigated as a therapeutic strategy to enhance cAMP signaling in a broad range of diseases, including several types of cancers, as well as in various neurologic, dermatological, and inflammatory diseases.