Disruption of HPV 16 E1 and E2 genes in precancerous cervical lesions

The presence of HPV 16 E1 and E2 genes was detected in cervical cytological samples using polymerase chain reaction assays. A total of 48 samples were analyzed from patients with HPV 16 infections associated with 13 low-grade cervical intraepithelial neoplasia and 35 high-grade cervical intraepithelial neoplasia. Disruption/deletion sites, within E1 and E2 genes, were detected using 6 primer pairs spanning the entire gene sequences. This technique is not able to recognize mixed DNA forms (integrated plus episomal DNA); therefore, it detects only the presence of pure integrated DNA. Both E1 and E2 genes were detected in 84.6% and in 62.9% of low and high-grade lesions, respectively. The rate of samples with disrupted/deleted genes was significantly higher in high-grade cervical intraepithelial neoplasia than in low-grade cervical intraepithelial neoplasia (P < 0.05). In high-grade cervical intraepithelial neoplasia the disruption/deletion pattern involved both E1 and E2 genes and E2 gene was always involved, while in the low grade cervical intraepithelial neoplasia only E1 gene was involved. In conclusion, in high-grade cervical lesions E2 gene seems a suitable target to identify HPV 16 DNA integration into cellular genome.