Randomized controlled trials are recognized as having the strongest type of study design for generating evidence on prevention of disease. They are, however, the most labor- and time-intensive and costly to conduct. Intervention studies on the recurrence of colorectal adenomas might serve as a model with relevance to the etiology of not only large bowel cancer but also other sites of neoplastic development. The results of intervention studies assessing the effect of calcium, antioxidants and fiber on the recurrence of colorectal adenomas have been conflicting, showing a beneficial effect in some cases but not others. There are methodological issues in intervention trials for colorectal cancer, regarding study subjects, end point, dose, interaction, duration and timing, and compliance, for example. Although relatively few trials have been conducted to investigate the effects of an explicit dietary change on the recurrence of adenoma, results obtained so far have demonstrated that modifying the lifestyle may reduce the risk of chronic diseases including cancer. Furthermore, recent progress in molecular epidemiology has allowed clarification of many of the molecular mechanisms underlying susceptibility. Eventually, it may be possible to target intervention programs to genetically susceptible individuals, including molecular targeting, for the prevention of cancer.

OBJECTIVETo investigate the relationship between polymorphisms of the methylenetetrahydrofolate reductase (MTHFR) C677T or A1298C and the response to fluoropyrimidine (5-FU)-based chemotherapy in advanced stomach cancer (SC).

METHODS75 cases with advanced SC were analyzed. All patients were treated with 5-FU-based chemotherapy and DNA of peripheral blood leukocytes was obtained before therapy. MTHFR genotypes were detected by PCR-RFLP method.

RESULTS(1) Of all the cases, the frequencies of MTHFR C677T C/C, C/T and T/T genotype were 32.0%, 44.0% and 24.0%, while the frequencies of MTHFR A1298C A/A, A/C and C/C genotype were 69.3%, 29.3% and 1.3%, respectively. The overal response rate to 5-FU-based chemotherapy was 29.3%. (2) The response rate to therapy among MTHFR C677T T/T genotype patients (83.3%) was significantly higher than the C677T C/T genotype (15.2%, chi(2) = 22.27, P = 0.000) or the C677T C/C genotype (8.3%, chi(2) = 23.44, P = 0.000). As compared with patients with C677T C allele, patients with C677T T/T genotype had a 7.64-fold sensitivity to 5-FU-based chemotherapy (adjusted for sex, age, prior adjuvant therapy and chemotherapy program, 95% CI: 3.14 - 18.62). The response rate to therapy among patients with MTHFR A1298C A/A genotype (36.5%) was significantly higher than patients with A1298C C allele (13.0%, chi(2) = 4.19, P = 0.041, adjusted OR = 3.75, 95% CI: 0.94 - 14.87). The response rate to therapy among patients with MTHFR C677T T/T and A1298C A/A genotypes (86.7%) was significantly higher than other groups of C677T and A1298C genotypes (15.0%, Fisher exact: P = 0.000, adjusted OR = 6.57, 95% CI: 2.8 - 15.6). (3) The incidence rates of nausea/vomiting in MTHFR C677T T/T, C/T or A1298C A/A genotypes were significantly higher than other genotypes, but the incidence rates of other treatment-related adverse reaction in MTHFR C677T or A1298C genotypes were not significantly different.

CONCLUSIONThese results in the present study suggested that the polymorphisms of MTHFR were associated with clinical response to 5-FU-based chemotherapy, suggesting that MTHFR genotypes could identify advanced SC patients that would be responsive to 5-FU-based chemotherapy.

Adult ; Aged ; Antimetabolites, Antineoplastic ; therapeutic use ; Drug Resistance, Neoplasm ; genetics ; Female ; Fluorouracil ; therapeutic use ; Genotype ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Restriction Fragment Length ; Stomach Neoplasms ; drug therapy ; enzymology

OBJECTIVETo investigate the relationship between polymorphisms of methylenetetra-hydrofolate reductase gene 1298A-->C (MTHFR 1298A-->C) and its susceptibility of esophageal cancer (EC).

METHODSWe conducted a case-control study with 141 cases of EC and 228 population-based controls in Huaian city of Jiangsu province, China. Epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects. MTHFR genotypes were identified by polymerase chain reaction.

RESULTS(1) The frequency of MTHFR 1298AA, AC and CC genotype were 63.8%, 34.0% and 2.1% in EC and 71.9%, 28.1% and 0.0% in controls, respectively (chi(2)(MH) = 6.69, P = 0.035). The frequency of the MTHFR 1298C allele was 0.19 for EC and 0.14 for controls. (2) Individuals having MTHFR 1298C allele and smoking habit were at a significantly higher risk of developing EC (adjusted OR = 3.48, 95% CI: 1.57 - 7.71) compared with those who having AA genotype but no smoking habit. Individuals having MTHFR 1298C allele and habit of frequent alcohol drinking were at an increased risk of developing EC (adjusted OR = 2.91, 95% CI: 1.20 - 7.08) compared with those with AA genotype and low consumption of alcohol. Individuals having MTHFR 1298C allele but no habit of tea drinking had a 3.52-fold (95% CI: 1.64 - 7.54) increased risk of developing EC compared with tea drinkers with AA genotype. As compared with subjects having AA genotype, low consumption of alcohol, no smoking habit but having habit of drinking tea, the individuals having 1298C allele, habits of frequent alcohol drinking, smoking but no habit of tea drinking had a 12.64-folds (95% CI: 1.39 - 114.65) increased risk of developing EC.

CONCLUSIONResults in the present study suggested that there was a coordinated effect between MTHFR 1298 genotypes and habits of smoking, alcohol drinking and tea consumption in the development of EC.

Adult ; Aged ; Alcohol Drinking ; Case-Control Studies ; China ; Esophageal Neoplasms ; enzymology ; genetics ; Female ; Gene Frequency ; Genetic Predisposition to Disease ; genetics ; Genotype ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Middle Aged ; Polymerase Chain Reaction ; Polymorphism, Genetic ; Smoking

OBJECTIVEIn order to study the relation between polymorphisms of methylenetetrahydrofolate reductase C677T (MTHFR) and susceptibility of stomach cancer (SC).

METHODSWe conducted a case-control study with 107 cases of SC and 200 population-based controls in Huaian city of Jiangsu province, China. The epidemiological data were collected, and DNA of peripheral blood leukocytes was obtained from all of the subjects. MTHFR genotypes were detected by PCR-RFLP method.

RESULTS(1) The frequency of MTHFR variant genotypes (C/T + T/T) among the cases (79.4%) was significantly higher than the controls (68.5%) (P = 0.041 6); the crude OR for SC was 1.78 (95% CI: 0.99 - 3.22). After adjustment for sex and age, the OR for SC was 1.89 (95% CI: 1.08 - 3.32). (2) Subjects who had MTHFR variant genotypes and having smoking habit were at a significantly higher risk of developing SC (OR = 7.72, 95% CI: 2.23 - 26.79) compared with those who had wild-type homozygotes (C/C) genotype and no smoking habit. Individuals who had variant genotypes and who had habit of frequent alcohol drinking were at an increased risk of developing SC (OR = 3.08, 95% CI: 1.30 - 7.23) compared with those with C/C genotype and low consumption of alcohol. As compared with subjects with C/C genotype and low consumption of alcohol and no smoking habit, individuals who had variant genotypes and who had habits of frequent alcohol drinking and smoking had 12.96 (95% CI: 2.76 - 70.46) folds risk developing SC.

CONCLUSIONSThese results in the present study suggested that the polymorphisms of MTHFR C677T was associated with risk of developing SC, and there was a coordinated effect between MTHFR genotypes and habits of smoking and alcohol drinking in the development of SC.

Alcohol Drinking ; Female ; Genetic Predisposition to Disease ; Humans ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; Middle Aged ; Oxidoreductases Acting on CH-NH Group Donors ; genetics ; Point Mutation ; Polymorphism, Genetic ; Risk Factors ; Smoking ; Stomach Neoplasms ; epidemiology ; genetics

OBJECTIVETo evaluate interactions between lifestyle, methylanetetrahydrofolate reductase gene (MTHFR) and polymorphisms in the 3'-untranslated region (3'-UTR) of the thymidylate synthase gene (TS) with reference to development of stomach cancer (SC).

METHODSWe conducted a case-control study with 107 cases of SC and 200 population-based controls in Huaian city of Jiangsu province, China. TS genotypes were identified by polymerase chain reaction.

RESULTS(1) The frequencies of TS genotypes (+6 bp/+6 bp, +6 bp/-6 bp and -6 bp/-6 bp) among the cases were 5.6%, 47.7% and 46.7% and among the controls were 9.0%, 54.0% and 37.0%, respectively. Individuals identified as -6 bp/-6 bp genotype had a slightly higher risk for SC than those individuals with +6 bp alleles (the crude OR = 1.49, 95% CI: 0.90 - 2.47; adjusted OR = 1.36, 95% CI: 1.00 - 1.78, P = 0.047). (2) Individuals having TS -6 bp/-6 bp genotype and having smoking habit were at a significantly higher risk of developing SC (adjusted OR = 2.79, 95% CI: 1.51 - 5.18) compared with those who had +6 bp alleles with no smoking habit. Individuals having TS -6 bp/-6 bp genotype and habit of frequent alcohol drinking were at an increased risk of developing SC (adjusted OR = 1.76, 95% CI: 1.07 - 2.90) compared with those with +6 bp alleles and low consumption of alcohol. As compared with individuals with +6 bp alleles and who had habit of tea drinking, individuals who had TS -6 bp/-6 bp genotype and but without habit of tea drinking had an increased risk of developing SC (adjusted OR = 2.34, 95% CI: 1.43 - 3.82). (3) Individuals with TS -6 bp/-6 bp genotype and with MTHFR T alleles had an increased risk of developing SC (adjusted OR = 2.67, 95% CI: 1.07 - 6.70) compared with those with +6 bp alleles and with MTHRF C/C genotype.

CONCLUSIONResults in the present study suggested that there was a combined effect between lifestyle, MTHFR C/T or T/T genotype and TS -6 bp/-6 bp genotype in the development of SC.

Alcohol Drinking ; adverse effects ; Case-Control Studies ; China ; epidemiology ; Female ; Genetic Predisposition to Disease ; Humans ; Life Style ; Male ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Point Mutation ; Polymorphism, Genetic ; Risk Factors ; Smoking ; adverse effects ; Stomach Neoplasms ; epidemiology ; genetics ; Tea ; chemistry ; Thymidylate Synthase ; genetics

OBJECTIVETo evaluate the relationship between dietary folate intake and genetic polymorphisms of 5, 10-methylenetetrahydrofolate reductase (MTHFR) with reference to breast cancer risk.

METHODSA case-control study was conducted with 669 cases and 682 population-based controls in Jiangsu province of China. MTHFR C677T and A1298C genotypes were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methods. Dietary folate intake was assessed by using an 83-item food frequency questionnaire. Odds ratios (OR) were estimated with an unconditional logistic model.

RESULTSThe frequencies of MTHFR C677T C/C, C/T and T/T genotypes were 32.37% (202/624), 48.88% (305/624) and 18.75% (117/624) in cases and 37.66% (235/624), 48.24% (301/624) and 14. 10% (88/624) in controls, respectively. The difference in distribution was significant (chi2 = 6.616, P = 0.037), the T/T genotype being associated with an elevated OR for breast cancer (1.62, 95% CI: 1.14 -2.30). The frequencies of MTHFR A1298C A/A, A/C and C/C were 71.47% (446/624), 27.08% (169/624) and 1.44% (9/624) in cases and 68.11%(425/624), 30.13% (188/624) and 1.76% (11/624)in controls,with no significant differences found (chi2 = 1.716, P= 0.424). Folate intake of cases [(263.00 +/- 137.38) microg/d] was significantly lower than that of controls [(285.12 +/- 149.61) microg/d] (t = -2. 830, P =0.005). Compared with the lowest tertile (< or = 199.08 microg/d) of folate intake, the adjusted OR for breast cancer in the top tertile (> or = 315.11 microg/d) was 0.70 (95% CI: 0.53 -0.92). Among individuals with the MTHFR A1298C A/A genotype,adjusted OR for breast cancer were 0.89 (95% CI: 0.62 - 1.27) and 1.69 (95% CI: 1.20 - 2.36) for the second to the third tertile of folate intake compared with the highest folate intake group (X2trend = 11.372, P = 0.001).

CONCLUSIONThe findings of the present study suggest that MTHFR genetic polymorphisms,and dietary intake of folate may modify susceptibility to breast cancer.

Breast Neoplasms ; epidemiology ; genetics ; metabolism ; Case-Control Studies ; China ; epidemiology ; Diet ; Female ; Folic Acid ; metabolism ; Genotype ; Humans ; Methylenetetrahydrofolate Reductase (NADPH2) ; genetics ; Polymorphism, Genetic ; Surveys and Questionnaires