| Objective:Cervical cancer is one of the most common malignancies of the worldwide.It is second to breast cancer as the most common malignancies in incidence,Shanxi Province is the one of the high-rate areas of cervical cancer in China,with the mortality rate of 36 per100000 every year.To explore the relationship of folate acid and the polymorphism of MTHFR with cervical cancer risk,and the effect of their interactions in the development of cervical cancer on the base of investigating the risk factors extensively,The result would offer some new evidences for the etiology of cervical cancer. Methods:A hospital-based case-control study was conducted in Shanxi Tumor Hospital from Jane 2005 to June 2005.The study included 111 women newly diagnosed by pathology with cervical cancer and 111 control with hysteromyoma.Cases were frequency-matched to control by age(±3 y).All participants required Shanxi resident,Han people,who had cerebrovascular disease,haemolyticus disease,digestive system disease,VitB supplement within 3 months and other dysplasias were considered ineligible for study.A standardized questionnaire was used to elicit risk factors of cervical cancer,including demographic and lifestyle information,sexual and reproductive history and oral contraceptives use.The food frequency questionnaire was used in this study,almost 60 food items or categories were selected to provide an estimate of foods rich in folate before 5 years of disease diagnosed.Color photograph illustrating the three most representative serving sizes were used to assist subjects in estimating amounts consumed.The exfoliated cervical cell specimen was abstained when the cervical cytological smears,3ml blood sample were drawn in the before breakfast.HPV16 DNA was detected by PCR amplification,serum folate was measured by radiobinding assay,Genotyping for the MTHFR C677T polymorphism was analyzed by PCR-RLFP.Statistical analysis was conducted using the Stata7.0 and Spss11.0,t-test,χ2-test,Wilxocon rank sum test,test for trend,grade analysis,unconditional Logistic regress and dichotomy was applied. Results: (1)Occupation,incomes,culture degree,cigarette smoking,menopause,age at first sexual intercourse and parity related to cervical cancer risk.(2)HPV16 infection rate is significantly higher in case than it in control (61.36%vs 21.83%),the odds ratios is 4.95(95%CI=2.49-9.83).(3)case had lower means of dietary folate consumption than controls(t=2.64,p=0.01),dietary quartile was based on the frequency distribution among the control,the highest quartile was used as the referenc,there was no significant relation with cervical cancer risk.(4)Serum folate in cases is significantly lower than it in control,using women in highest as reference category,serum folate was dose-respond relationship (χ2trend =17.37,p=0.00) between cervical cancer and serum folate.(5) Folate and HPV16-infected showed a significant interaction in the development of cervical cancer.(6)The distribution of the MTHFR C677T alleles fit the Harding-Weinberg equilibrium.The frequencies of CC,CT,and TT genotype were 18.02%,47.75%,34.23%,respectively in case and were 29.73%,54.05%,16.22% respectively in control (χ2=10.77,p=0.01).Adjusted odds ratio computed for T/T versus C/C was 2.91(95%CI=1.09-7.75),adjusted odds ratio computed for TT/non-T/T were 2.58(95%CI=1.22-5.45).(7)Between folate deficiency & HPV16-infected and MTHFR mutation showed a trend of gene-environment interaction , but which had no statistically significant difference. Conclusions: (1) Peasant,smoking,multiparty,earlier age at first intercourse were associated with increased risk of cervical cancer ,Menopausal ,higher education degree,higher incomes were the protect factors of cervical cancer.(2)HPV16 infection was the etiology associated with the development of cervical cancer.(3)Low folate status might be a risk for cervical cancer,regardless of high-risk HPV16 infection and other risk factors,which had joined effect with HPV16 infection in the development of cervical cancer.(4)The mutant type homozyg... |
