MTHFR polymorphisms, dietary folate intake and breast cancer risk in Chinese women.
To evaluate the relationship between dietary folate intake and genetic polymorphisms of 5,10-methylenetetrahydrofolate reductase (MTHFR) with reference to breast cancer risk, we conducted a case-control study with 669 cases and 682 population-based controls in the Jiangsu Province of China. MTHFR C677T and A1298C genotypes were identified using PCR-RFLP (restrictrion fragment length polymorphism) methods. Dietary folate intake was assessed using an 83-item food frequency questionnaire. Odds ratios (ORs) were estimated with an unconditional logistic model. The frequencies of MTHFR C677T C/C, C/T and T/T genotypes were 32.37, 48.88 and 18.75% in cases and 37.66, 48.24 and 14.10% in controls, respectively. The difference in distribution was significant (chi(2)=6.616, P=0.037), the T/T genotype being associated with an elevated OR (adjusted for age, menopausal status, body mass index (BMI), income, work intensity and status of smoking and drinking) for breast cancer (1.62, 95% confidence interval (95% CI): 1.14-2.30). The frequencies of MTHFR A1298C A/A, A/C and C/C were 71.47, 27.08 and 1.44% in cases and 68.11, 30.13 and 1.76% in controls, respectively, with no significant differences being found (chi(2)=1.716, P=0.424). A significant inverse relationship was observed between folate intake and breast cancer risk. Compared with the lowest tertile of folate intake, the adjusted OR for breast cancer in the top tertile was 0.70 (95% CI: 0.53-0.92). However, no significant interaction was observed between folate intake and the MTHFR C677T polymorphism. Among individuals with the MTHFR A1298C A/A genotype, adjusted ORs for breast cancer were 0.89 (0.62-1.27) and 1.69 (1.20-2.36) for the second to the third tertile of folate intake compared with the highest folate intake group (tread test, P=0.0008). The findings of this study suggest that MTHFR genetic polymorphisms and dietary intake of folate may modify susceptibility to breast cancer.
Gao
Chang-Ming
CM
Division of Epidemiology, Jiangsu Province Institute of Cancer Research, Nanjing, China. gaocm888@126.com
Tang
Jin-Hai
JH
Cao
Hai-Xia
HX
Ding
Jian-Hua
JH
Wu
Jian-Zhong
JZ
Wang
Jie
J
Liu
Yan-Ting
YT
Li
Su-Ping
SP
Su
Ping
P
Matsuo
Keitaro
K
Takezaki
Toshiro
T
Tajima
Kazuo
K
D000328:Adult; D000368:Aged; D044466:Asian People / Q000235:genetics; D001943:Breast Neoplasms / Q000201:enzymology / Q000235:genetics*; D016022:Case-Control Studies; D016001:Confidence Intervals; D004032:Diet; D005247:Feeding Behavior; D005260:Female; D005492:Folic Acid / Q000378:metabolism*; D020022:Genetic Predisposition to Disease; D006801:Humans; D042965:Methylenetetrahydrofolate Reductase (NADPH2) / Q000235:genetics*; D008875:Middle Aged; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*
D005492:Folic Acid; D042965:Methylenetetrahydrofolate Reductase (NADPH2)