Among these, the PKA pathway serves as a critical junction: it can be activated both by G protein-coupled receptor (GPCR) ligands (such as ADM in breast cancer, PTHrP in ccRCC, and PTH and ANP in CKD and by β-adrenergic receptors (e.g. catecholamines in burns). This evidence concerns the gene PTHLH and nonpapillary renal cell carcinoma.