ABSTRACT
Objective To explore the effect of folic acid and DNA methyltransferase 1 (DNMT1) on cervical cancer and cervix precancerous lesion. Methods 100 patients with cervix squamouscell carcinoma (SCC), 101 patients with cervical intraepithelial neoplasm (CIN) and 109 patients with cervix inflammation (CI) diagnosed by histology were included in this study. Radioimmunoassay (RIA), polymerase chain reaction (PCR) and Western blot were used to detect the levels of serum folate, HPV16 infection and the expression of DNMT1 protein,respectively. Results The average levels of serum folate were (2.60 ± 1.61) ng/ml, (3.14 + 2.08) ng/ml and (3.32+1.74) ng/ml,and the expression of DNMT1 protein were 2.40 + 0.99,1.88 + 0.33 and 0.89 ± 0.29 in the group of SCC, CIN and CI, respectively.The relationship of folate levels and DNMT1 protein expression showed inverse correlation (r=-0.186, P=0.00l). The results in our study indicated that there was an additive interaction between low-level of serum folate and high-expressionof DNMT1 protein related to the risk of CIN and SCC, with OR value as 2.50(95%C/: 1.21-9.22) and 6.03 (95%C/: 2.79-21.72) respectively. The relative excessrisk of interaction (RERI) , attributableproportion of interaction (API) and synergy index (S) were 0.92, 0.36 and 2.59 in the CIN group while 2.47, 0.41 and 1.96 in the SCC group. Conclusion The low level of serum folate and high expression of DNMT1 protein seemed to be associated with high risk of cervical cancer and its precancerous lesion. It suggested that there might be a synergistic action between serum folate and DNMT1 in the progression of cervix carcinogenesis.