Background: The purpose of this study was to report associations between p16 status, clinicopathologic characteristics, and outcomes for head and neck squamous cell carcinoma of unknown primary (CUP).
Methods: Specimens of squamous cell CUP were reanalyzed. Human papillomavirus (HPV) status was determined by p16 stain. A tissue microarray (TMA) was constructed to evaluate biomarkers potentially prognostic in head and neck squamous cell carcinoma (HNSCC).
Results: A majority of the population (n = 26; 74%) was p16 positive (+). Prognostic factors benefiting survival were p16+ status (p < .0001), absence of macroscopic extracapsular extension (ECE; p = .004), younger age (p = .01), and higher grade (p = 0.007). The prognostic implication of worse overall survival (OS) with macroscopic ECE (p = .009) remained significant when limited to patients who were p16+ (p = .002). Exploratory TMA between unknown primary and controls suggested a biomolecular difference between squamous cell CUP and known-primary cancer.
Conclusion: The majority of patients with squamous cell CUP were p16+, indicative of HPV association. P16 staining and ECE seem to be the most prognostic features in squamous cell CUP.
Keywords: concurrent chemotherapy; extracapsular extension (ECE); human papillomavirus (HPV); tissue microarray; unknown primary.
© 2014 Wiley Periodicals, Inc.