[1204] High Risk Human Papillomavirus Is Not a Common Etiologic Agent in Nasopharyngeal Carcinoma.

Aatur D Singhi, Joseph A Califano, William H Westra. The Johns Hopkins Hospital, Baltimore, MD

Background: The human papillomavirus (HPV), a cause of squamous cell carcinomas of the oropharynx, has also been implicated as an etiologic agent in carcinomas of the nasopharynx. The purpose of this study was to determine the frequency of high risk HPV in carcinomas of the nasopharynx, and to assess p16 immunohistochemical staining as a method for distinguishing HPV-related from Epstein Barr virus (EBV)-related carcinomas involving the nasopharynx.
Design: We performed p16 immunohistochemistry and in-situ hybridization for EBV and high risk HPV on 45 carcinomas of the nasopharynx. For HPV-positive cases, imaging studies were reviewed in an attempt exclude secondary extension from the oropharynx.
Results: By in-situ hybridization, 34 (76%) carcinomas were EBV+/HPV-, 7 (16%) were EBV-/HPV-, and 4 (9%) were EBV-/HPV+. EBV was more likely to be detected in carcinomas from non-Caucasian than Caucasians (96% vs. 50%, p < 0.001). Conversely, HPV was more likely to be detected in carcinomas from Caucasian than non-Caucasian (16% vs. 0%, p = 0.03). Of the patients with HPV-positive carcinomas and available staging information, all 3 were found to have inferior extension into the palatine tonsil. All HPV-positive carcinomas were p16 positive by immunohistochemistry, but none of the HPV- negative carcinomas were p16 positive (100% vs. 0%, p < 0.001).
Conclusions: High risk HPV can be detected in a subset of carcinomas involving the nasopharynx, but many if not all of these likely represent secondary extension from an oropharyngeal primary. P16 immunohistochemistry is a reliable marker for separating EBV-related from HPV-related carcinomas of Waldheyer's ring.
Category: Head & Neck

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 144, Tuesday Afternoon


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