Green Tea Fights Colon Cancer

COLUMBIA, S.C.Green tea appears to target initial stages of colon carcinogenesis, but early administration is critical for chemoprevention (Carcinogenesis, ePub July 17, 2007; DOI:10.1093/carcin/bgm161). Researchers from the University of South Carolina used the ApcMin mouse model and a colon selective carcinogen to induce a four-fold increase in number of colon tumors. Mice then received water or a 0.6-percent (w/v) solution of green tea as the only source of beveragehydration. Green tea treatment started at the 8th week of age and lasted for four or eight weeks. Green tea significantly inhibited the formation of new adenomas but was ineffective against larger tumors. In a mechanistic study, the researchers found green tea decreased total levels of the early carcinogenesis biomarker beta-catenin and its downstream target cyclin D1, and inhibited the formation of tumors overexpressing those biomarkers. However, green tea did not alter COX-2 expression, nor reduce the number of adenomas expressing COX-2. The researchers concluded green tea specifically targets initial stages of colon cancer.