[1261] Lacking Caspid Protein Expression in p16 Positive Head and Neck Squamous Cell Carcinoma Using HPV-1 Immunohistochemistry

Alyaa Al-Ibraheemi, Songlin Zhang. UT Health, Houston, TX

Background: The incidence of head and neck squamous cell carcinoma (HNSCC) have risen steadily in US and Northen Europe. They are associated with high risk human papillomorirus (HPV). HPV-positive cancer is associated with better patient survival than HPV-negative cancer. Different testing methods have been used for HPV detection, such as in situ hybridization (ISH) or polymerase chain reaction (PCR). P16 immunohistochemistry has been shown to be a sensitive surrogate marker for HPV with a good specificity. Serum HPV caspid proteins, such as major (L1) and minor (L2), have been associated with HPV positive head and neck cancer, and lacking caspid protein expression in uterine cervical intraepithelial neoplasia (CIN) is associated with high grade squamous dysplasia. The caspid protein expression has been shown in head and neck squamous papillomas, but it is not known in HNSCC.
Design: Immunohistochemistry for p16 and HPV-1 was introduced to our laboratory since March 2010. Anti HPV-1 clone K1H8 has been shown immunoreactive with paraffin sections of formalin-fixed HPV infected tissue including HPV 6,11,16,18,31,33,42,51,52,56 and 58. There are total 33 cases of HNSCC with p16 and/or HPV-1 results during March 2010 to August 2012. H&E-stained sections and IHC slides were available in all cases. P16 and HPV-1 were both performed on 20 cases; p16 only in 11 cases; and HPV-1 only in 2 cases. The 33 HNSCC cases include 6 tongue base, 9 tonsils, 5 oral tongue, 7 larynx, 3 neck lymph nodes and 3 posterior oral pharynx. Two cases of laryngeal squamous papilloma were included.
Results: P16 was positive in 15 cases (48.4%), and 13/15 cases showed strong and diffuse positive. The 2 cases with focal p16 positivity were 1 oral tongue SCC and 1 posterior oral pharynx SCC. P16 was positive in 83.3% tongue base SCC, 57.1% tonsil SCC, 66.7% neck metastatic SCC 100% posterior oral pharynx SCC, 20% oral tongue SCC, and 0% larynx SCC. HPV-1 was negative in all 22 cases including the 11 p16 positive HNSCC cases. The two squamous papillomas were positive for HPV-1 but negative for p16.
Conclusions: PCR for HPV L1 gene is one of the gold standard methods for detecting the HPV infection in HNSCC. The value of IHC for HPV caspid proteins was unknown. Our study showed complete lacking caspid protein expression in HNSCC using anti HPV-1. HPV-1 has no diagnostic value for detecting possible HPV infection in HNSCC. HPV-1 is sensitive for HPV associated squamous papillomas. Our study showed that p16 positive rate was high in oralpharyngeal SCC such as tongue base, tonsil and posterior oral pharynx.
Category: Head & Neck

Wednesday, March 6, 2013 9:30 AM

Poster Session V # 193, Wednesday Morning


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