Prevalence and clinical features of human papillomavirus in head and neck squamous cell carcinoma in Okinawa, southern Japan

Previous studies from Okinawa, a subtropical island in southern Japan, demonstrated a higher prevalence of human papillomavirus (HPV) in oral carcinoma and a higher incidence of oral and pharyngeal carcinoma than those for mainland Japan. The present study aims to investigate epidemiologic and clinical features of HPV in head and neck squamous cell carcinoma (HNSCC) in Okinawa. A total of 150 DNA samples from 150 Okinawan patients with head and neck squamous cell carcinoma (HNSCC) were screened for HPV sequences by PCR using three consensus primer sets, and HPV types were determined by direct sequencing. The samples were consisted of 46 cases from the hypopharynx, 44 from the oropharynx, 16 from the larynx, 25 from the oral cavity, 10 from the maxillary sinus, and 9 from the nasopharynx. HPV DNA was detected in 45 (30.0%) HNSCCs, and HPV-16 was identified in 86.7% of positive specimens. The highest prevalence of the HPV sequence was found in oropharyngeal carcinomas (50.0%), especially in tonsillar cancer (63.6%). Multivariate analysis showed that oropharyngeal carcinoma (P = 0.002; OR = 5.34; 95% CI = 1.83-15.58), oral cavity carcinoma (P = 0.012; OR = 4.94; 95% CI = 1.43-17.10), and histological poor differentiation (P = 0.011; OR = 4.25; 95% CI = 1.39-13.04) each independently increased the prevalence of HPV infection. The present study reveals that patients with HNSCC, e.g., oropharyngeal and oral cavity carcinomas, in Okinawa have relatively high HPV-16 positive rates and low HPV-18 positive rates comparing with mainland Japan.