Dietary isothiocyanates, GSTM1, GSTT1, NAT2 polymorphisms and bladder cancer risk

Abstract

TXIsothiocyanates (ITCs) are nonnutrient compounds in cruciferous vegetables with anticarcinogenic properties. ITCs down-regulate cytochrome P-450 biotransformation enzyme levels, activate Phase II detoxifying enzymes and induce apoptosis. On the other hand, ITCs also serve as a substrate for GSTs. Experimental evidences suggest that ITCs have anticarcinogenic effect on bladder cancer. Therefore, we evaluated dietary intake of ITCs, GSTM1, GSTT1 and NAT2 polymorphisms, and bladder cancer risk in a case-control study. There were 697 newly diagnosed bladder cancer cases identified from The University of Texas M. D. Anderson Cancer Center and 708 healthy controls matched to cases by age (65), gender and ethnicity. Participants underwent an in-person interview, in which epidemiologic and food frequency questionnaires were administered to collect demographic and dietary intake data. Median ITC intake per day was statistically significantly lower in cases than in controls (0.23 vs. 0.33, p < 0.001). High ITC intake was associated with 29% decreased risk of bladder cancer [Odds ratio (OR) 5 0.71, 95% confidence interval (CI) 5 0.57, 0.89]. The protective effect was more evident in older individuals (64-years-old), men, ever smokers and heavy smokers in stratified analysis. Compared with NAT2 rapid acetylator, NAT2 slow acetylator had an increased risk of bladder cancer in Caucasians (OR 5 1.31, 95% CI 5 1.02, 1.69). There was no main effect associated with the GSTM1 or GSTT1 genotypes. The protective effect of ITCs against bladder cancer was not modified by GSTM1, GSTT1 or NAT2 genotypes. This is the first epidemiological report that ITCs from cruciferous vegetable consumption protect against bladder cancer. ' 2007 Wiley-Liss, Inc.

Dietary Intake of Vegetables and Fruits and the Modification Effects of GSTM1 and NAT2 Genotypes on Bladder Cancer Risk

“…DNA was isolated from peripheral blood lymphocytes by standard SDS/ proteinase K method. Genotyping procedures for GSTM1 and NAT2 were described previously (32). In our laboratory, strict quality control procedures for genotyping are implemented to ensure high genotyping accuracy.…”

Proximate, Mineral and Antinutrient Compositions of Indigenous Okra (Abelmoschus esculentus) Pod Accessions: Implications for Mineral Bioavailability

“…Dietary fiber is known to alter the coronary environment in such a way as to protect against colorectal diseases (Ekumankama 2008). It provides protection by increasing fecal bulk, which dilutes the increased colonic bile that occurs with high fat diet (Dillard and German 2000;Zhao et al 2007). When found in excess, it may bind some essential trace elements leading to deficiency of some minerals such as iron and zinc (Ekwumemgbo et al 2014).…”

Consumption of Raw Cruciferous Vegetables is Inversely Associated with Bladder Cancer Risk

“…Recently, Zhao et al (40) estimated the amount of dietary isothiocyanates consumed in a study in Singapore based on food frequency questionnaires, and found that high isothiocyanate intake was inversely associated with bladder cancer risk (OR, 0.71; 95% CI, 0.57-0.89). Furthermore, this association between the intake of isothiocyanates and bladder cancer risk was more evident in ever smokers and heavy smokers in stratified analyses, which is consistent with our findings.…”