Mutation of p53 Gene and Infection of Human Papillomavirus in Oral and Oropharyngeal Carcinoma / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Oral and oropharyngeal squamous cell carcinomas (SCC) are diseases that are largely attributed to environmental exposure. Tobacco use and alcohol consumption are well-established risk factors. However, small proportions of oral and oropharyngeal SCCs occur also in nonsmokers and nondrinkers, suggesting the presence of other risk factors. We investigated etiologic role of Human papillomavirus (HPV) in patients with oral and oropharyngeal SCCs and the association between infection with HPV and p53 alteration in oral and oropharyngeal SCCs. MATERIALS AND METHOD: Tumor tissues from 46 patients with oral and oropharyngeal SCCs were examined for the presence of HPV type 16 and 18 genome by polymerase chain reaction (PCR), and the p53 status of each tumor was analysed by sequencing and immunohistochemistry. RESULTS: Thirty-six (78.3%) of 46 cases revealed overexpression of p53 protein and 14 (30.4%) had p53 mutation. The rate of p53 overexpression was much higher in smokers than in nonsmokers (p=0.003). HPV was detected in 8 (17.4%) of 46 cases and all were HPV type 16. As compared with HPV-negative carcinomas, HPV-positive cancers were less likely to occur among smokers (p=0.001) and to have p53 mutation and p53 overexpression (p=0.007), and had a moderately and poorly differentiated cancer characteristic. CONCLUSION: The alteration of p53 is related to smoking which is counteractive to the presence of HPV infection, which can be considered as an independent etiologic factor in oral and oropharyngeal SCCs.