ACE and colorectal carcinoma: RAS components are targeted by three common classes of drugs in hypertension treatment: β-blockers, which reduce renin production; ACE inhibitors (ACEIs); and angiotensin receptor blockers (ARBs), which antagonize AT1R. Retrospective epidemiological studies show that patients taking these medications have lower incidence of polyp formation, CRC and metastasis, with ARBs having the greatest effect [16].