Gao Chang-Ming, Kazuo Tajima, Tang Jin-Hai, Cao Hai-Xia, Ding Jian-Hua, Wu Jian-Zhong, Wang Jie, Liu Yan-Ting, Li Su-Ping, Su Ping, Keitaro Matsuo, Toshiro Takezaki
Division of Epidemiology, Jiangsu Province Institute of Cancer Research, Nanjing, China.
Zhonghua Yu Fang Yi Xue Za Zhi. 2009 Jul;43(7):576-80.
To evaluate the relationship between dietary folate intake and genetic polymorphisms of 5, 10-methylenetetrahydrofolate reductase (MTHFR) with reference to breast cancer risk.
A 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.
The 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).
The findings of the present study suggest that MTHFR genetic polymorphisms,and dietary intake of folate may modify susceptibility to breast cancer.
评估膳食叶酸摄入量与5,10 - 亚甲基四氢叶酸还原酶（MTHFR）基因多态性与乳腺癌风险之间的关系。
在中国江苏省进行了一项病例对照研究，共纳入669例病例和682例基于人群的对照。采用聚合酶链反应 - 限制性片段长度多态性（PCR - RFLP）方法鉴定MTHFR C677T和A1298C基因型。通过一份包含83个条目的食物频率问卷评估膳食叶酸摄入量。采用非条件逻辑模型估计比值比（OR）。
病例组中MTHFR C677T C/C、C/T和T/T基因型频率分别为32.37%（202/624）、48.88%（305/624）和18.75%（117/624），对照组中分别为37.66%（235/624）、48.24%（301/624）和14.10%（88/624）。分布差异具有统计学意义（χ2 = 6.616，P = 0.037），T/T基因型与乳腺癌的OR升高相关（1.62，95%CI：1.14 - 2.30）。病例组中MTHFR A1298C A/A、A/C和C/C基因型频率分别为71.47%（446/624）、27.08%（169/624）和1.44%（9/624），对照组中分别为68.11%（425/624）、30.13%（188/624）和1.76%（11/624），未发现显著差异（χ2 = 1.716，P = 0.424）。病例组的叶酸摄入量[（263.00 ± 137.38）μg/d]显著低于对照组[（285.12 ± 149.61）μg/d]（t = -2.830，P = 0.005）。与叶酸摄入量最低三分位数（≤199.08μg/d）相比，最高三分位数（≥315.11μg/d）的乳腺癌调整后OR为0.70（95%CI：0.53 - 0.92）。在MTHFR A1298C A/A基因型个体中，与叶酸摄入量最高组相比，叶酸摄入量第二至第三三分位数的乳腺癌调整后OR分别为0.89（95%CI：0.62 - 1.27）和1.69（95%CI：1.20 - 2.36）（χ2趋势 = 11.372，P = 0.001）。
本研究结果表明，MTHFR基因多态性和膳食叶酸摄入量可能会改变乳腺癌易感性。
