[1199] Is p16 Better and More Cost Effective Than HPV ISH for Detection of HPV-Associated Head and Neck Squamous Cell Carcinoma?

Thad M Primeaux, Jaiyeola Thomas. LSUHSC-Shreveport, LA

Background: HPV-associated squamous cell carcinoma of the head and neck (HNSCC) has been identified as a distinct clinical and biological entity when compared to its non-HPV counterparts. Clinically, this subset of tumors has been shown to respond more favorably to chemotherapy and radiation, making their identification of paramount importance. Various detection methods including PCR, DNA in-situ hybridization (ISH) and p16 IHC are being used to determine the HPV tumor status. This study aims to determine the usefulness of p16 as a first-line marker for identification of HPV-associated HNSCC.
Design: 37 consecutively diagnosed HNSCC from 2009-2010 were reviewed with demographic data, lesional site, histologic subtypes, and tumor grade documented. All cases were simultaneously stained with p16 antibody (CINtec, Westborough, MA) and HR-HPV DNA ISH using HPV III INFORM probe (Ventana, Tuscan, AZ), which is a send-out test in our laboratory. The staining reactions of both techniques were analyzed and correlated with clinicopathological parameters.
Results: 32 cases had complete data and staining results. 9/32 (28.1%) and 16/32 (50.0%) were positive with HR-HPV ISH and p16 IHC, respectively, with HPV-/p16+ (7 cases), HPV+/p16+ (9 cases) and HPV-/p16- (16 cases). No cases stained HPV+/p16-. 7/16 (43.8%) p16+ cases were basaloid subtype, while all p16+ cases were located in the tonsil or oropharyngeal region. p16 staining (nuclear & cytoplasmic)(figure1) was more intense, easier to detect and interpret, more sensitive, and cheaper than HPV-ISH(figure2).

Conclusions: HPV-/p16+ cases may indicate HPV-associated tumors related to HPV subtypes not identified by the ISH probe or HPV unrelated mutational Rb gene inactivation. Conversely, HPV+/p16- cases may be due to inactive infection. Importantly, p16 IHC was easier to interpret, more sensitive and cost-effective than HPV-ISH in HNSCC, and may be able to discriminate active from latent HPV infection.
Category: Head & Neck

Tuesday, March 1, 2011 1:00 PM

Poster Session IV # 134, Tuesday Afternoon


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