[1168] Detection of Human Papilloma Virus and P16 Expression in High Grade Adenoid Cystic Carcinoma of the Head and Neck.

Jennifer M Boland, Ellen D McPhail, Joaquin J Garcia, Jean E Lewis, David J Schembri Wismayer. Mayo Clinic, Rochester, MN

Background: Squamous cell carcinoma (SCC) of the head and neck, particularly non-keratinizing squamous cell carcinoma and basaloid squamous cell carcinoma (BSCC), may be difficult to distinguish from high grade adenoid cystic carcinoma (HGACC). Oropharyngeal SCC is frequently associated with human papilloma virus (HPV), especially HPV 16, which is thought to cause p16 overexpression by functional inactivation of the retinoblastoma protein. As such, p16 is widely considered a surrogate marker for HPV infection. However, the incidence and relevance of p16 expression and HPV infection in HGACC of the head and neck is unknown.
Design: The Mayo Clinic pathology database was searched for cases of HGACC of the head and neck in which resection specimens with paraffin blocks were available. Twelve cases were identified (6 submandibular gland, 4 parotid gland, sublingual gland, nasal cavity). All cases were tested by immunohistochemistry for p16 expression and in situ hybridization (ISH) for high and low risk HPV. Clinical histories were obtained from existing medical records.
Results: All study cases exhibited focal p16 immunoreactivity (100%). Of the 12 cases, only one (nasal) was positive for HPV by ISH (8%).
Conclusions: These findings suggest that the presence of HPV infection in HGACC is infrequent, even in the presence of p16 overexpression. Nevertheless, HPV positivity should not be used to exclude the possibility of HGACC when the differential diagnosis includes both BSCC and HGACC. Moreover, although p16 overexpression is often used as a surrogate marker for HPV infection in SCC, it cannot be used in this manner in the setting of HGACC.
Category: Head & Neck

Monday, February 28, 2011 9:30 AM

Poster Session I Stowell-Orbison/Surgical Pathology/Autopsy Awards Poster Session # 159, Monday Morning


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