Chemoprevention of colorectal cancer : experimental and clinical aspects

Colorectal cancer is a leading cause of cancer-related mortality worldwide. Therefore, an appropriate prevention strategy should be urgently established. Chemoprevention involves the use of oral agents to suppress the development of cancer. Recent progress in the molecular analysis of colorectal cancer has revealed many candidate molecules for chemoprevention. Many new agents targeting these molecules have also been developed. These agents are largely classified into three categories : 1) Signal transduction modulators including epidermal growth factor (EGF) receptor inhibitors, anti-vascular endothelial growth factor (VEGF) antibodies, and inhibitors of oncogene products. 2) Epigenetic modulators including peroxisome proliferative activated receptor (PPAR)-γ agonists, estrogen receptor (ER)-β , and histone deacetylase inhibitors. 3) Anti-inflammatory modulators including cyclooxygenase (COX)-2, EP 1-4, and NF-kB. Of these agents, some actually proceeded to human clinical trials, and have been shown to be active chemopreventive agents.