MARK2 and malignant colon neoplasm: Therapeutic activation of the cGMP/PKG pathway offers a promising approach for the prevention and treatment of colon cancer.[52] Ras proteins activated multiple downstream signaling pathways, including the Raf-1 proto-oncogene, serine/threonine kinase/mitogen-activated protein kinase kinase/extracellular signal-regulated kinases pathway and the PI3K/Akt pathway.