Viruses associated with potentially malignant and malignant oral mucosal lesions.

Oral squamous cell carcinoma (OSCC) and oral epithelial dysplasia (OED) are known to be associated with high tobacco and/or alcohol consumption. A viral aetiology for OSCC and OED has been proposed, in particular human papillomavirus (HPV). The overall aim of the present work was to determine the geographical prevalence and viral interactions of HPV, CMV, EBV and HHV-8 in oral squamous cell carcinoma (OSCC) and potentially malignant oral mucosal diseases (oral epithelial dysplasia (OED), oral lichen planus (OLP) and proliferative verrucous leukoplakia (PVL)), as well as a range of salivary gland tumours and samples from HIV infected individuals. Extraction of DNA from archival paraffin-embedded lesional tissues of histopathologically proven OSCC, OED, OLP, PVL, and normal oral mucosa of HIV-infected individuals, various salivary gland tumours and normal oral mucosa was performed. Viral DNA of HPV, human herpesvirus (HHV-8), Epstein-Barr virus (EBV) and cytomegalovirus (CMV) was detected by nested polymerase chain reaction (PCR), and the genotype of HPV was determined using reverse line blotting hybridisation (RLB). The proportion of HPV-DNA detected in OSCC was higher when compared to all other examined mucosal and salivary gland lesions. There were trends of an increased prevalence of HPV within OED, PVL and OLP when compared to normal-control oral mucosa. The proportion of HHV-8 was not increased in any oral mucosal lesion except in HIV-individuals when compared to normal-control, which was expected. With respect to EBV, the proportion of EBV in PVL samples was increased when compared to normal- control. The CMV-DNA was detected in a low percentage of both PVL and OED samples when compared to the normal-control. There was no evidence of any interactions between any herpes viruses with HPV in OSCC. It is concluded that HPV infection may be associated with OSCC and OED