Relationship between the methylation of L1 3' and long control region gene of HPV16 DNA and it's pathogenicity

Abstract

Quantifiably and located measure the methylation rate of 21 cytosine-phosphate-guanosine (CpG) sites in the 3' region of L1 gene and long control region (LCR) gene of HPV16 DNA in asymptomatic patients, cervical intraepithelial neoplasia (CIN) patients, and cervical cancer patients. To analysis the relationship between HPV16 methylation and it's pathogenicity. Chosen 30 cases with HPV16 positive in each group. Firstly, extract DNA from the remaining cells of liquid-based cytology specimen and bisulfite treatment DNA, then amplify the 3' region of L1 gene and LCR gene, test the methylation rate of 21 CpG sites of HPV16 DNA in three groups. All of the 5 CpG sites in E6/E7 promoter (31, 37, 43, 52, 58) were hypomethylation in cervical cancer group (21.86%, 28.15%, 21.37%, 26.15%, 15.48%, respectively), hypermethylation in asymptomatic group, and middle-methylation in CIN group, in which there were significant difference among three groups (all P < 0.01). The CpG site in 7032, 7091, 7136 of the 3' region of L1 gene was also different methylated among three groups (all P < 0.01). Hypermethylation was found in cancer group (18.89%, 27.72%), hypomethylation was found in asymptomatic group (2.71%, 6.95%) in 7032 and 7091. In 7136, the highest methylation was detected in CIN (66.45%), the lowest in asymptomatic (34.85%), middle in cancer group (46.43%). The methylation status of CpG sites in the 3' region of L1 gene and E6/E7 promoter of HPV16 is significant different among three groups, which is likely to anticipate the pathogenesis of CIN and cervical cancer.