Incidence of human papillomavirus infection in oral leukoplakia. Indications for a viral aetiology.

Epidemiological and experimental studies have indicated a possible role of human papillomavirus (HPV) in the etiopathogenesis of oral premalignant lesions and tumors. The aim of this study was to establish the incidence of HPV infection and the typing of genotypes in some patients with nonmalignant oral cavity pathology and healthy subjects. We selected 80 subjects affected by the following pathologies: oral leukoplakia (20), squamous cell papilloma (6), various forms of stomatitis (30), lichen planus (15), burning mouth syndrome (BMS, 9). Ten healthy subjects were used as control. The patients underwent a brushing directly on the lesion or on the lower gums and on the dorsal surface of the tongue and a new, sensitive method of in situ hybridization (ISH) with colorimetric signal amplification was used for HPV detecting. The samples were tested with a Mix probe, which identifies most of the HPV genotypes and, in positive cases, the specific probe for the 6-11, 31-33-51 and 16-18 genotypes, was used. Leukoplakia and papilloma were , therefore, associated with the HPV infection, differently from the other pathologies and healthy oral mucosa (chi-squared < 0.005). In conclusion, according to our findings, HPV is a specific risk factor for the development of oral premalignant lesions.