Lack of Association between High-risk Human Papillomaviruses and Oral Squamous Cell Carcinoma in Young Japanese Patients

Background: Human papillomaviruses (HPV) may play an important role as one of the possible etiologiesof oral squamous cell carcinoma (OSCC). The present study aimed to investigate the association between HPVand OSCC in young Japanese patients by examining the presence of HPV DNA and surrogate markers in OSCCtissues. Materials and Methods: Forty young patients with OSCC whose surgical specimens were available wereanalyzed and compared with 40 patients randomly recruited from a pool of patients aged >40 years. HPV DNAwas detected using the polymerase chain reaction-based AMPLICOR® HPV test, and surrogate markers ofHPV infection were analyzed using immunohistochemical techniques to detect p16INK4a and p53. Results: Onlytwo (5%) young patients and one (2.5%) older patient were positive for HPV DNA. p16INK4a overexpressionwas identified in six (15%) young patients. p53 staining levels were not high in tissues of most young patients(27 patients, 67.5%). HPV DNA status did not significantly correlate with p16INK4a expression levels. Profiles ofincreased levels of p16INK4a expression with diminished levels of p53 staining were not associated with the presenceof HPV DNA. The combined p53 with p16INK4a profiles were significantly correlated with alcohol consumptionin younger patients (p=0.006). Conclusions: Results of the present study indicate that HPV is less likely to causeOSCC in young Japanese patients, and the p16INK4a expression level is not an appropriate surrogate marker forHPV infection in OSCC.