PRKACA and cancer: To validate the findings that the cAMP signaling is suppressed in these cancers, we used The Human Protein Atlas14 to investigate the expression of protein kinase-A (PKA) catalytic subunit (PRKACA), a key kinase of the cAMP pathway that mediates phosphorylation of multiple downstream cAMP pathway substrates, comparing tumor samples to non-tumor controls (Supplementary Figure S1).