Colorectal Cancer
Copyright ©2005 Baishideng Publishing Group Inc. All rights reserved.
World J Gastroenterol. Mar 14, 2005; 11(10): 1473-1480
Published online Mar 14, 2005. doi: 10.3748/wjg.v11.i10.1473
Vegetable/fruit, smoking, glutathione S-transferase polymorphisms and risk for colorectal cancer in Taiwan
Chih-Ching Yeh, Ling-Ling Hsieh, Reiping Tang, Chung Rong Chang-Chieh, Fung-Chang Sung
Chih-Ching Yeh, Institute of Environmental Health, National Taiwan University, Taipei 100, Taiwan, China
Ling-Ling Hsieh, Chung Rong Chang-Chieh, Department of Public Health, Chang Gung University, Tao-Yuan 333, Taiwan, China
Reiping Tang, Colorectal Section, Chang Gung Memorial Hospital, Taipei 244, Taiwan, China
Fung-Chang Sung, Institute of Environmental Health, China Medical University, Taichung 404, Taiwan, China
Author contributions: All authors contributed equally to the work.
Supported by National Science Council No. 89-2314-B-002-373, 90-2320-B-002-123 and 91-2320-B-002-121; National Health Research Institute No. 85-HR-516, 86-HR-516, and 87-HR-516
Correspondence to: Dr. Fung-Chang Sung, Institute of Environment Health, China Medical University, 91 Hsueh-Shih Road, Taichung 404, Taiwan, China. fcsung@mail.cmu.edu.tw
Telephone: +886-4-2205-4070 Fax: +886-4-2201-9901
Received: August 26, 2004
Revised: August 28, 2004
Accepted: September 25, 2004
Published online: March 14, 2005
Abstract

AIM: To investigate the colorectal cancer risk associated with polymorphic GSTM1, GSTT1 and GSTP1 and the effect of diet and smoking.

METHODS: With consents, genotypes of the genes were determined using PCR methods for 727 cases and 736 sex and age-matched healthy controls recruited at a medical center in the Northern Taiwan. Nurses who were blind to the study hypothesis conducted interviews with study participants for the information of socio-demographic variables, diet and smoking.

RESULTS: There was no significant association between GSTM1 genotypes and the disease. Men, not women, with GSTT1 null genotype were at significant risk of colorectal cancer, but limited to rectal tumor, and in men aged 60 years and less. The corresponding association with the GSTP1 with G allele compared to GSTP1 A/A genotype was at borderline significance. Compared to men with GSTT1 present and GSTP1 A/A combined, men with both GSTT1 null and GSTP1 with G allele genotypes were at significant risk (odds ratio (OR) = 1.91, 95% confidence interval (CI) = 1.21-3.02), also limited to the rectal tumor and younger men. The beneficial effects of vegetable/fruit intake on colorectal cancer were much higher for men with GSTT1 present (OR = 0.32, 95%CI = 0.20-0.50) or GSTP1 A/A genotypes (OR = 0.40, 95%CI = 0.25-0.64). These effects remained significant for women. But, the greatest protective effect from vegetable/fruit intake for women was observed in those with GSTT1 null or GSTP1 with G allele genotypes. In addition, non-smoking men benefitted significantly from combined effect of higher vegetable/fruit intake and GSTT1 present or GSTP1 A/A genotypes with OR = 0.17 and 0.21 respectively.

CONCLUSION: This study suggests that the GSTT1 gene can modulate the colorectal cancer risk and vegetable/fruit-related colorectal cancer risk, particularly in men of no smoking history.

Keywords: Colorectal cancer; Glutathione S-transferase; Polymorphisms; Vegetables; Smoking