title: Squamous cell carcinoma of the oral cavity often overexpresses p16 but is rarely driven by human papillomavirus.
abstract: OBJECTIVE
  Human papillomavirus (HPV) is a causal and prognostic factor for oropharyngeal cancer, but its role in squamous cell carcinoma of the oral cavity (SCCOC) is unclear. We sought to clarify HPV's role in SCCOC.
  
  
  METHODS
  Patients with newly diagnosed SCCOC (N=460) were prospectively recruited, treated, and followed at one institution. p16/HPV status was determined by p16 immunohistochemistry (IHC) (N=210), PCR-based HPV 16/18 E6/7 DNA testing (N=403), and/or HPV in situ hybridization (ISH) (N=178). Kaplan-Meier curves and log-rank tests were used to compare survival by p16/HPV status.
  
  
  RESULTS
  p16 expression was detected in 30% of tumors (62/210) and HPV 16/18 E6/7 DNA in 28% (114/403), although correlation between these two assays was poor (r=-0.01). Patients with p16-positive tumors were more likely to be younger and have primary tumors of the oral tongue. Only 4% of tumors (7/171) were positive for HPV by ISH. Comparisons of patients with p16-positive and p16-negative tumors, patients with HPV-positive and HPV-negative tumors by PCR, and patients with HPV-positive and HPV-negative tumors by ISH showed no significant differences in disease-specific or disease-free survival by p16/HPV status. When we applied a more stringent definition of HPV positivity based on a combination of assay results, only 10 of 166 tumors were HPV positive, and there were no significant differences in demographic, exposure, clinical, or survival characteristics between these patients and the 156 HPV-negative patients.
  
  
  CONCLUSIONS
  Very few patients with SCCOC have HPV-driven tumors. SCCOC that overexpresses p16 may be a unique subset deserving of further study.
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Mark E
authors.initials: ME
authors.lastname: Zafereo
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Li
authors.initials: L
authors.lastname: Xu
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Kristina R
authors.initials: KR
authors.lastname: Dahlstrom
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Carlo A
authors.initials: CA
authors.lastname: Viamonte
authors.affiliation: Department of Pathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Adel K
authors.initials: AK
authors.lastname: El-Naggar
authors.affiliation: Department of Medicine, Duke University School of Medicine, Duke Cancer Institute, Duke University Medical Center, Durham, NC 27710, United States.
authors.forename: Qingyi
authors.initials: Q
authors.lastname: Wei
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States; Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States.
authors.forename: Guojun
authors.initials: G
authors.lastname: Li
authors.affiliation: Department of Head and Neck Surgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States; Department of Epidemiology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, United States. Electronic address: esturgis@mdanderson.org.
authors.forename: Erich M
authors.initials: EM
authors.lastname: Sturgis
mesh_terms: D000328:Adult; D000368:Aged; D052685:Alphapapillomavirus / Q000502:physiology*; D002294:Carcinoma, Squamous Cell / Q000378:metabolism* / Q000821:virology; D005260:Female; D019942:Genes, p16; D006801:Humans; D008297:Male; D008875:Middle Aged; D009062:Mouth Neoplasms / Q000378:metabolism* / Q000821:virology
keywords: Human papillomavirus; Oral cavity cancer; Oral tongue cancer; p16 protein