[409] Use of p16 Immunocytochemistry in Fine Needle Aspiration Biopsies of Metastatic Head and Neck Squamous Cell Carcinoma

RA Grimes, MT Garcia, M Jorda, P Ganjei-Azar, A Mejias, A Ferrell, C Gomez-Fernandez. Jackson Memorial Hospital/ University of Miami, Miami, FL; University of Miami Sylvester Comprehensive Cancer Center, Miami, FL

Background: High-risk human papillomavirus (HPV) is recognized as an independent risk factor for a subset of head and neck squamous cell carcinomas (HNSCC). HPV-related HNSCC is most often localized to the oropharynx, where greater than 50% of the tumors are associated with HPV-16 infection. The initial presentation for 13% of HNSCC patients is a neck mass. A fine needle aspiration (FNA) is the standard tool used to confirm the diagnosis of metastatic HNSCC. Despite a thorough clinical and radiologic workup, the primary site remains unknown in up to two thirds of these patients. Expression of p16 has been described as a marker of transcriptionally active HPV infection, as well as an indicator of improved survival and response to therapy in HNSCC. We sought to determine the value of using p16 immunocytochemistry (ICC) on FNA biopsies of neck masses with metastatic HNSCC to identify the HPV-related site of origin, and potentially enhance therapeutic options.
Design: We reviewed 90 FNA biopsies of neck metastases from patients with HNSCC from the cytopathology files at our institution. Primary sites included 43 from the oropharynx (19 tonsil, 17 base of tongue, 7 oropharynx NOS) and 47 from non-oropharyngeal sites (27 oral cavity, 11 larynx, 4 skin, 3 hypopharynx, 2 nasopharynx). Papanicolaou-stained slides were directly subjected to ICC, using the p16 antibody (Dako) and LSAB methodology. Tumors were classified as either p16 positive (strong, diffuse nuclear and cytoplasmic staining) or negative.
Results: Twenty-seven of 90 (30%) cases expressed p16 by ICC. Twenty (74%) of these p16 positive cases were metastases from oropharyngeal primary sites. There was a significantly higher proportion of positive expression for p16 among patients with a primary oropharyngeal carcinoma (20 of 43; 47%) versus those whose primary tumor was non-oropharyngeal (7 of 47; 15%) (p=0.0013).
Conclusions: p16 is expressed in 30% of FNA biopsies of neck masses diagnostic for metastatic HNSCC and is a reliable indicator of metastases from the oropharynx. The use of p16 ICC to detect HPV-related HNSCC that present in the neck may provide important prognostic information and improved therapeutic options. Finally, Papanicolaou-stained slides from FNA samples of neck masses may be directly used for the evaluation of p16 expression.
Category: Cytopathology

Monday, March 22, 2010 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 49, Monday Morning


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