High-resolution melting analysis of HPV-16L1 gene methylation: A promising method for prognosing cervical cancer

Abstract

Objective: Methylation-sensitive high-resolution melting (MS-HRM) is a new technique for DNA methylation analysis, but it is rarely used for the detection of viral DNA methylation. In this study, we investigated the HPV-16L1 gene methylation that is detected by MS-HRM as a potential biomarker for prognosing cervical dysplasia and cancer.

Design and methods: A total of 114 HPV-16 infected patients (normal (17), CIN1 (25), CIN2 (29), CIN3 (32), SCC (11)) who underwent liquid-based cytology test and biopsy were included in this study. 17 cases with HPV-16 infection and negative cytologic and histologic results served as the control group. The HPV-16L1 gene methylation statuses of these samples were investigated using a methylation-sensitive high-resolution melting (MS-HRM) assay after bisulfite modification.

Results: The HPV-16L1 gene methylation statuses of all the 114 specimens were successfully detected by MS-HRM, and we observed increasing methylation levels in severe lesions, as determined using histologic assays. In addition, the methylation levels of CIN2+ (CIN2, CIN3 and SCC) were significantly higher than that of CIN2- (normal and CIN1, P<0.001). When taking CIN2+ as the reference, our HPV-16L1 DNA methylation assay achieved 91.7% sensitivity and 59.5% specificity, respectively.

Conclusions: The results of the present work demonstrated that HPV-16L1 gene methylation was closely associated with cervical precancerosis and cancer. Moreover, using MS-HRM to detect HPV-16L1 gene methylation may be a powerful assay for the triage of HPV-16-positive females, which could identify patients with high risk of invasive cancer.

Keywords: Cervical cancer; Cervical intraepithelial neoplasia; DNA methylation; HPV-16; High-resolution melting; L1 gene.