Moreover, pharmacological inhibitors, such as PF-2545920, ADT-061, and MCI-030, selectively elevate intracellular cAMP and/or cGMP, activating PKA or PKG pathways, in ovarian, colorectal, and other cancer models suggesting a tumor-specific preference for cyclic nucleotide regulation, possibly due to kinetic properties of the enzyme or compensatory cAMP degradation by other PDE isoforms. Here, PRKG1 is linked to cancer.