Human papillomavirus & WHO type i nasopharyngeal carcinoma

Objectives: Nasopharyngeal carcinoma (NPC) is a rare cancer in the U.S. that has a well-established association with Epstein-Barr virus (EBV) for WHO types II/III but less so for WHO type I. Given the rise in oropharyngeal tumors positive for high risk human papillomavirus (HPV) and the unique biology of WHO type I NPC, we chose to examine the relationship between HPV and WHO type I NPC. Study Design: Retrospective casecomparison study. Methods: A search of a large multidisciplinary cancer center tumor registry identified 183 patients seen from January 1999 to December 2008 with incident NPC and no history of prior cancer. Available paraffinembedded tumor specimens (N=30) were analyzed for HPV status by insitu hybridization (ISH) and polymerase chain reaction (PCR) for HPV 16 and 18, EBV status by ISH, and p16 expression by immunohistochemistry. Demographic parameters, including race, smoking, and alcohol exposure were obtained from the medical records. Results: Patients with incident WHO-I NPC (N=18) tended to be smokers (66%) and only 17% were Asian, while for patients with incident WHO-II/III NPC (N=165), 44% were smokers and 24% were Asian. For WHO-I NPC patients with available paraffin blocks (N=8), 5 of 6 were HPV 16+ by PCR and 4 of 8 had HPV identified by ISH, while only 2 of 8 were EBV+. Of patients with WHOII/ III NPC and available archival tissue (N=22), 60% were EBV+ and only one was HPV positive by ISH. Conclusions: These results suggest that WHO type I NPC may be associated with oncogenic HPV, though larger studies are needed to verify these findings.