Distribution of human papilloma virus 16 in oral sites affected by squamous cell carcinoma

Abstract

<h3>Objectives</h3> Studies have indicated that cases of HPV-associated squamous cell carcinoma (SCC) in the oropharynx and the oral cavity are on the rise. However, the distribution of human papilloma virus (HPV) in different sites of the oral cavity affected by oral SCC (OSSC) has not been well characterized. The present study was designed to investigate the anatomic sites of HPV-16 infection associated with OSCC in the oral cavity and correlate HPV-16 positivity with tumor suppressor gene expression and clinical/pathologic features of OSCC. <h3>Methods</h3> The archives of oral pathology at the University of Florida College of Dentistry were accessed for demographic, clinical, and histologic data of 97 OSCC cases, and their histologic slides were obtained under the approved institutional review board protocol. Histologic specimens were stained for HPV-16 by immunohistochemistry (IHC), and the positive samples were further analyzed for HPV DNA by in situ hybridization (ISH). <h3>Results</h3> Ninety-seven patients with OSCC comprising 53 (54.63%) males and 44 (45.36%) females with ages ranging from 40 to 95 years were included. Twenty (20.6%) had a history of smoking, and 16 (16.49%) drank alcohol; the information for the rest of the sample was unavailable. The oral sites of OSCC include the following: gingiva 34 (35%), palate 25 (25.77%), tongue 16 (16.49%), buccal mucosa 14 (14.43%), and floor of the mouth 8 (8.24%). The degree of OSCC differentiation showed 34 (35%) for well differentiated, 32 (32.98%) for moderately differentiated, and 31 (31.95%) for poorly differentiated. Of 14 p16-positive cases detected by IHC (14.43%), 12 (85%) were positive for ISH specific for HPV DNA. The tongue and the palate showed the highest prevalence of HPV-related OSCC (4 of 16 [25%] and 6 of 25 [24%], respectively), followed by the gingiva (4 of 34 [12%]). Strong positivity for p16 detected by IHC and HPV DNA by ISH was found in well and moderately differentiated OSSC (7 of 34 [20%] and 5 of 32 [15%], respectively). <h3>Conclusions</h3> Our study identified 14% of cases of OSCC to be associated with HPV, with the tongue and the palate being the most prevalent sites. This finding may indicate that the route of the viral transmission for OSCC may be similar to the one associated with oropharyngeal cancer.