Characterization of three novel human papillomavirus types isolated from oral rinse samples of healthy individuals.

BACKGROUND: Despite the strong evidence of HPV infection as the etiological agent in a subset of oral cancer, oral α-HPV detection is rare in healthy individuals, and little is known of the existing of novel HPV types in oral cavity. OBJECTIVE: We determined whether novel HPV types can be isolated from oral rinse samples collected from healthy individuals. STUDY DESIGN: We performed rolling circle amplification (RCA) coupled with degenerated PCR assay on 48 oral rinse samples to amplify novel HPV types. Full length HPV DNA was cloned using long range PCR. Quantitative type specific Taqman assays were used to determine the prevalence of novel HPV types in 158 archived oral tissue samples. RESULTS: We were able to isolate four novel human papillomavirus types. Full length HPV DNA was cloned for three of the four novel HPV types. All four HPV types belong to the genus Gammapapillomavirus (γ-PV), where HPV 171 is most closely related to HPV 169, showing 88% similarity; HPV 172 is most closely related to HPV 156, showing 70% similarity; HPV 173 is most closely related to HPV 4, showing 73% similarity; oral sample lavage (OSL) 37 is most closely related to HPV 144, showing 69% similarity. Finally, we showed that HPV 173 was rarely present in oral tissues (2/158), HPV 172 was only detected in normal oral tissues (25/76), and HPV 171 was more prevalent in malignant oral tissues (17/82 vs. 10/76, p=0.21). CONCLUSIONS: Novel γ-HPV types are present in oral cavity of healthy individuals.