Effects of ginger supplementation on cell-cycle biomarkers in the normal-appearing colonic mucosa of patients at increased risk for colorectal cancer: results from a pilot, randomized, and controlled trial.

To estimate the effects of ginger on apoptosis, proliferation, and differentiation in the normal-appearing colonic mucosa, we randomized 20 people at increased risk for colorectal cancer to 2.0 g of ginger or placebo daily for 28 days in a pilot trial. Overall expression and distributions of Bax, Bcl-2, p21, hTERT, and MIB-1 (Ki-67) in colorectal crypts in rectal mucosa biopsies were measured using automated immunohistochemistry and quantitative image analysis. Relative to placebo, Bax expression in the ginger group decreased 15.6% (P = 0.78) in the whole crypts, 6.6% (P = 0.95) in the upper 40% (differentiation zone) of crypts, and 21.7% (P = 0.67) in the lower 60% (proliferative zone) of crypts; however, there was a 19% increase (P = 0.14) in Bax expression in the upper 40% relative to the whole crypt. While p21 and Bcl-2 expression remained relatively unchanged, hTERT expression in the whole crypts decreased by 41.2% (P = 0.05); the estimated treatment effect on hTERT expression was larger in the upper 40% of crypts (-47.9%; P = 0.04). In the ginger group, MIB-1 expression decreased in the whole crypts, upper 40% of crypts, and lower 60% of crypts by 16.9% (P = 0.39), 46.8% (P = 0.39), and 15.3% (P = 0.41), respectively. These pilot study results suggest that ginger may reduce proliferation in the normal-appearing colorectal epithelium and increase apoptosis and differentiation relative to proliferation--especially in the differentiation zone of the crypts and support a larger study to further investigate these results.