Clinical Significance of Human Papillomavirus DNA Test and p16 Overexpression in Oropharyngeal Cancer

Background and Objectives Oropharyngeal squamous cell carcinoma (OPSCC) can be caused by human papilloma virus (HPV) infection or other factors like smoking. The 8th Edition of the AJCC Cancer Staging Manual recommends different staging and treatment approaches based on etiology. Despite criticisms of its low specificity, the current guidelines suggest using p16 immunohistochemistry (IHC) as a surrogate marker for the HPV-related OPSCC. This study assessed the reliability of p16 as a surrogate marker by correlating the survival rates of OPSCC patients with the results of p16 IHC and HPV-DNA testing.Subjects and Method A retrospective analysis was performed on patients treated for tonsil squamous cell carcinoma at a tertiary medical institution between 1994 and 2018. All patients underwent p16 immunostaining and HPV-DNA chip tests. Out of 88 patients, 17 were excluded due to insufficient data or secondary primary cancer, leaving 71 patients.Results Among the 71 patients, 51 were p16 positive and 49 were HPV-DNA positive; both tests were associated with extended survival. However, discrepancies were noted in 18 patients: specifically, 11 patients were p16 positive but HPV-DNA negative, displaying a different survival pattern compared to HPV-associated and non-HPV-associated patients.Conclusion Both p16 immunostaining and HPV-DNA testing have their pros and cons. p16 immunostaining is cost-effective but has lower specificity. The study found discrepancies in 18 patients, suggesting that relying solely on p16 immunostaining may have limitations. It would be advisable to complement it with additional tests like the HPV-DNA chip test to predict the disease’s prognosis more accurately.