Table 1.

Summary of major chemopreventive agents

Agent	Target	Cancer prevention effect	References
Selective estrogen receptor modulators	Estrogen receptor (ER)	Reduce ER-positive breast cancer incidence in high-risk populations	11-18
Aromatase inhibitors	Aromatase	Reduce ER-positive breast cancer incidence in high-risk populations	16, 19, 20
Non-steroidal anti-inflammatory drugs	COX1/COX2	Reduce the occurrence of several cancers, mainly CRC and less notably stomach and esophageal cancers	21-25
Statins	HMG-CoA reductase	Observational studies showed long term statin use reduces incidences of gastrointestinal cancer	27-30
Metformin	Gluconeogenesis	Observational studies showed metformin use lowers risks of cancer incidence and mortality in diabetic patients	31-34

CRC, colorectal cancer; HMG-CoA, 3-hydroxy-3-methylglutaryl coenzyme A.