Cytokeratin 7 and 19 expression in oropharyngeal and oral squamous cell carcinoma

Purpose The precise etiopathogenesis of human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (OPSCC), and reasons for predilection for crypt epithelium, remain uncertain. The purpose of this study is to investigate the interaction between HPV and specific cytokeratins 7 (CK7) and 19 (CK19) in crypt epithelium. Methods This is a retrospective cohort study of patients presenting between 1999 and 2015 at a tertiary referral center. CK7 and CK19 positivity and H Scores were determined by immunohistochemistry. Disease-specific and overall survival rates were analyzed. Results There were 253 patients presenting with OPSCC (134), squamous cell carcinoma (SCC) of unknown primary site (22), and oral tongue SCC (97). Primary tumor CK7 and CK19 positivity and H Scores were significantly higher in HPV-positive OPSCC than HPV-negative OPSCC and oral tongue SCC. Higher CK19 Scores, but not CK7 Scores, were also seen in regional metastases from HPV-positive OPSCC than other sites. No impact on disease-specific or overall survival was identified on multivariate analysis. Conclusion The increased expression of CK7 and CK19 in HPV-positive OPSCC compared to HPV-negative disease supports the theory for a role for these cytokeratins in the etiopathogenesis of HPV-related OPSCC.