Although p@ protein expression , a surrogate marker of oncogenic human papillomavirus ( HPV ) infection , is recognized as a prognostic marker in oropharyngeal squamous cell carcinoma ( OPSCC ) , its prevalence and significance have not been well established in cancer of the oral cavity , hypopharynx , or larynx , collectively referred as non-OPSCC , where HPV infection is less common than in the oropharynx .