Disruption Events in the HPV18 E1 and E2 Genes in Precancerous Cervical Lesions

Human papillomavirus 18 (HPV18) is the second most oncogenic high-risk HPV genotype, after HPV16, and is responsible for about 15% of cervical cancer cases worldwide. The integration of high-risk HPV DNA into the host genome leads to the disruption of the E1 and/or E2 genes, which is considered a risk factor for viral-induced carcinogenesis. This study examined the disruption events of HPV18 E1 and E2 genes in precancerous cervical lesions to investigate the rates and sites of gene disruption in the Greek population. The complete E1 and E2 genes were amplified using three and four overlapping primer sets, respectively. Extensive analysis revealed that the disruption/deletion events of the E1 and E2 genes were detected in all grades of cytology-determined lesions, with high frequency. E2 gene disruption was significantly related to LSIL+ cases (Fisher's exact test, p = 0.022). No significant association was found in the analysis of the E1 gene. Additionally, no preferential sites of E1/E2 gene disruption were detected. This is the first study to provide evidence of disruption events of the HPV18 E1 gene. The data from the current analysis suggest that disruption of the E2 gene could be a significant marker for the progression of cytology-determined cervical dysplasia. However, future studies are required to evaluate whether different geographic populations have particular profiles regarding the rates and sites of gene disruption to further determine population-specific biomarkers.