Human papilloma virus in squamous cell carcinoma of the head and neck.

B216

Background: Human papilloma virus (HPV) contributes to the pathogenesis of head and neck squamous cell carcinoma (SCC), and previous studies have demonstrated a higher prevalence of HPV16 in oropharyngeal SCCs than oral SCCs or laryngeal SCCs. Methods : Individuals with pathologically confirmed squamous cell carcinoma of the head and neck participating in a multicenter study of biomarkers and epidemiologic risk factors through the University of Michigan Head and Neck SPORE program were eligible for inclusion. Paraffin-embedded tissue was examined by a pathologist, and areas of normal, dysplasia, and invasive cancer were circled for microdissection. HPV testing was performed using the GP5+/GP6+ reverse line blot method. Adequacy of amplifiable DNA was assessed using PCR for the beta-globin gene. Results : Microdissected DNA derived from 361 samples in 227 patients were tested for the presence of 37 different HPV types. The prevalence of HPV-positive cancers was 17.6% (40/227). HPV16 was identified in 39/227 cases and HPV18 identified in 1/227 cases. No other HPV type was identified. HPV16 was also identified in 3/67 (4.5%) normal mucosa samples and 8/69 (11.6%) areas of dysplasia. All cancers from patients whose normal mucosa demonstrated HPV16 were also HPV16 positive. The prevalence of HPV was strongly associated with tumor site: oropharynx (36.0%), hypopharynx (20.0%), oral cavity (2.1%), and larynx (0%), p<0.0001. The only case of nasopharyngeal carcinoma in the study was HPV positive. HPV was less common among cancers in females than males (OR= 0.45, 95% CI = 0.17 - 1.22). The mean age of HPV positive cases was similar to the mean age of HPV negative cases (58.6 vs. 57.9 respectively, p=0.63). Cancers arising in never smokers were slightly more likely to be HPV positive than ever smokers (OR = 1.5, 95% CI = 0.67 - 3.36). Conclusion : HPV16-associated squamous cell carcinomas represent an etiologically distinct subset of cancers of the head and neck. Consistent with prior studies, cancers of the oropharynx are more likely to have detectable HPV than other tumor sites. In addition, HPV positive tumors also appear to differ by other epidemiologic features, including gender and possibly smoking.