Background: Recently, the incidences of oral cavity and oropharyngeal squamous cell carcinomas have increased and they are common in several regions of the world. Many risk factors are attributed to oral cavity and oropharyngeal cancers, including betel nut chewing, tobacco exposure, oral hygiene, alcohol consumption and infection by the human papilloma virus 16 and 18.
Objective: To determine the prevalence of HPV16&18 in the oral cavity and oropharyngeal squamous cell carcinoma in Rajavithi Hospital.
Material and Method: The examination samples were collected from Formalin-fixed, paraffin-embedded (FFPE) tissue blocks from 78 Patients at Rajavithi Hospital, between 1st September 2011 and 30th September 2013. The detection of HPV16 and HPV18 was carried out using real time PCR technique.
Results: HPV DNA was detected in 78 samples (in 7 oropharyngeal specimens and 71 in the oral cavity). Three cases were positive for HPV16 and only 1 case was positive for HPV18. HPV16&18 were detected in 3.85% and 1.28% of all samples respectively. The only factor associated with HPV 16&18 infection was age.
Conclusion: The prevalences of human papilloma virus (HPV16 and 18) infection in the oral cavity and oropharyngeal squamous cell carcinoma in this study were found to be low (5.13%). Human papilloma virus 16 and 18 infection may not play an important role in this group of Thai patients.

Keywords: Human papillomavirus 16 and 18, Oral cavity, Oropharyngeal, Squamous cell carcinoma