Abstract
Oropharyngeal squamous cell carcinoma (OPSCC) that are associated with human papilloma virus (HPV) infection carry a more favourable prognosis than those that are HPV-negative. For detection of HPV in tumor material, in situ hybridization and PCR-based methods have been used. Recently, p16 is suggested to be an excellent surrogate marker for HPV infection. The simplicity, low cost, and high sensitivity of p16 immunohistochemical analysis (IHC) have prompted consideration of replacing HPV DNA in situ hybridization and PCR-based methods. However, p16 overexpression could suggest pRB pathway disturbances unrelated to HPV. This issue has not yet been fully evaluated in Japan. We performed a retrospective analysis of the association between p16 expression and HPV status of 91 patients with OPSCC at Hokkaido University Hospital, Japan, between 1998 and 2011. Of the 91 patients with OPSCC, 29 were HPV-positive and 31 were p16-positive. The 3-year overall survival rates were 82.2% in the p16-positive subgroup and 65.1% in the p16-negative subgroup; these figures were significantly different. As combined HPV and p16 status, the 3-year overall survival rates were 91.1% (HPV+/p16+ groups, n=24), 60.0% (HPV+/p16- groups, n=5), 65.7% (HPV-/p16- groups, n=55), 60.0% (HPV-/p16+ groups, n=7).
Our results showed that the patients with HPV-/p16+ had poor prognosis as compared with the patients with HPV+/p16+; therefore, p16 IHC alone may not be a perfect surrogate marker for HPV infection.
