Comparative study of HPV16 integration in cervical lesions between ethnicities with high and low rates of infection with high-risk HPV and the correlation between Integration rate and cervical neoplasia

The etiology of a high incidence of cervical cancer in populations with a low human papillomavirus (HPV) infection rate is unclear. The current study aimed to investigate the role of HPV16 DNA integration in cervical lesions in women of Han and Uygur ethnicity and to explore the association between viral integration and a high cervical cancer morbidity with a low HPV infection rate. DNA was extracted from the biopsy specimens of cervical lesions of 379 patients of Uygur ethnicity and 464 patients of Han ethnicity, and multiple quantitative polymerase chain reaction (qPCR) assays were performed to determine the copy numbers of the HPV16 E2 and E6 genes. The copy number of the HPV16 DNA was evaluated according to the E2/E6 ratio. Among these cases, 122 Uygur and 121 Han specimens were found to be HPV16 positive. In the two populations, the percentage of cases with HPV16 integration (the sum of integrated-type infection only or a mixture of free-and integrated-type infection) increased with the grade of the cervical lesions (P<0.001). Within groups with the same cervical lesion grade, no significant differences in HPV16 integration were found between women of Uygur and Han ethnicity (rank sum test, P>0.05). No significant differences in the distribution of the HPV16 integration rate according to lesion grade were found in either population (P>0.05). When the two subpopulations were considered as one sample population, the integration rate significantly increased with lesion grade (P=0.02). These results indicate that the integration rate of HPV16 E2 may serve as a molecular biological marker for the development of cervical lesions.