ABSTRACT
Objective To quantifiably measure the methylation frequency of 18 CpG sites in the 3′region of L1 gene and long control region(LCR) gene of HPVl6 DNA,and study the relationship between HPVl6 DNA methylation and severity of cervical lesions. Methods A total of 10 cases Normal/low?grade squamous intraepithelial lesion(Normal/LSIL),10 cases of high?grade squamous intraepithelial lesion(HSIL),and 10 cases of cervical cancer(CC)were recruited for the study. The relationship between severity of cervical lesions and HPV16 DNA methylation was analyzed by bisultlte?pyrosequencing. Results The methylation rate was highest in Normal/LSIL at position 7 089 located in 3′?L1,followed by CC. The low?est was found in HSIL. The difference in methylation percentage among the three lesions was significant(P=0.006). In 7 134,the proportion meth?ylation was also different among three groups(P=0.01),difference in methylation percentage between Normal/LSIL and CC,as well as Normal/LSIL and HSIL was significant(P=0.038,0.017). Conclusion The methylation status of CpG sites 7 089 and 7 134 in the 3′region of L1gene is asso?ciated with the severity of cervical disease. The quantification of HPV DNA methylation can be used for cervical disease screening in clinical samples.