Abstract. Background Among head and neck squamous cell carcinomas (HNSCCs), the incidence of oropharyngeal SCC (OSCC) is increasing compared with carcinomas of other origins, thereby attracting public attention (1, 2). Like other malignancies in the upper gastrointestinal tract, OSCC is attributed to the carcinogenic effects of tobacco and alcohol (3). Prediagnosis cigarette smoking can be a prognostic factor for overall survival (OS) in OSCC patients (4). Therapeutic options for early stage OSCC include both surgery and radiotherapy as single treatment modality, while those for advanced stage include surgery, chemoradiation and chemotherapy (5, 6).On the other hand, in recent years, human papillomavirus (HPV) is known to be involved, in addition to drinking and smoking, in oropharyngeal carcinogenesis (1, 7-10). HPV is the most common sexually transmitted disease. However, the overwhelming majority of patients with HPV clear the infection. A small percentage of patients with HPV develop oncogenic HPV types, especially HPV-16, and consequently, SCCs can develop in such patients. HPV causes more than 5% of malignancies worldwide (1, 7-10). Over 70% of OSCCs are currently thought to be linked to oncogenic HPV infection. Immunohistochemistry for p16 protein is often used as a surrogate marker for oncogenic HPV in the oropharyngeal tissues (11, 12). The clinical profile of patients with HPV-related OSCC differs quite notably from that of non-HPV-related OSCC, and the clinical outcome for HPV-related OSCC is reported to be significantly better due to high sensitivity for radiation therapy (2,7,8).Numerous clinical studies have examined the role of transoral surgical resection (SR) for the treatment of oropharyngeal malignancies and have shown similar clinical outcomes and improved functional outcomes compared with chemoradiation therapies (5, 13). However, the relationship between p16 expression and prognosis in OSCC patients undergoing surgery has not been fully examined. Thus, there is urgent need for elucidating these issues. The aims of this study are therefore to clarify the relationship between p16 expression and prognosis in patients with OSCC undergoing surgery.
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