Human pathology
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Human papillomavirus (HPV) infection is an indicator of good response to chemoradiotherapy in oropharyngeal squamous cell carcinoma (OPSCC), and epidermal growth factor receptor (EGFR) is a molecular-therapeutic target in head and neck squamous cell carcinoma. Here we investigated the prevalence and prognostic significance of HPV infection and EGFR alteration in OPSCC. We analyzed the presence of high-risk HPV using in situ hybridization, protein expressions of p16 and EGFR using immunohistochemistry, and the EGFR gene copy number gain using chromogenic in situ hybridization (CISH) in 105 cases of OPSCC. ⋯ The EGFR CISH-negative OPSCCs had favorable prognosis irrespective of HPV infection. Our results suggest that EGFR gene copy number gain-positive tumors represent an HPV-negative, aggressive subgroup of OPSCCs. The molecular subclassification of OPSCCs based on HPV infection and EGFR status may serve as important information for appropriate therapeutic strategy.