Verrucous Carcinoma of the Head and Neck Lacks Transcriptionally-Active Human Papillomavirus
Kalyani R Patel, Rebecca D Chernock, Tian Zhang, Xiaowei Wang, Samir K El-Mofty, James S Lewis. Washington University in St. Louis, St. Louis, MO
Background: Studies have shown the presence of transcriptionally-active human papillomavirus (HPV) in squamous cell carcinomas (SCC) and in numerous SCC variants when they occur in the oropharynx. While HPV DNA can be found in many non-oropharyngeal SCC, transcriptionally-active HPV is quite rare. Verrucous carcinomas (VC) are a subtype of SCC characterized by warty appearance, locally destructive growth pattern, and lack of metastasis when not associated with an invasive SCC component. A few studies have shown variable amounts of HPV DNA and also p16 protein expression in verrucous lesions of the head and neck. However, no definitive link has been established between these tumors and HPV. In particular, VC has not been assessed for transcriptionally active HPV (mRNA).
Design: We performed a search of our pathology database for the keyword "verrucous" and after reviewing all cases, selected 49 which met our diagnostic criteria. The lesions were categorized into 3 groups on the basis of histologic features: pure VC (26/49), well differentiated SCC with verrucous features (SCC-VF) (17/49) and SCC arising in VC (SCC-VC) (6/49). SCC-VF were verrucous carcinomas with dysplasia or with minor invasive SCC (<2mm in depth). SCC-VC was VC with major invasive SCC (>2mm in depth). p16 immunostaining and RT-PCR for E6 and E7 mRNA of 13 high risk HPV types were performed. p16 was interpreted as positive only with both cytoplasmic and nuclear staining and was graded in quartiles for extent.
Results: Table 1 shows the p16 immunohistochemistry results by type.
|p16 Staining Extent||0||1+ (1-25%)||2+ (26-50%)||3+ (51-75%)||4+ (76-100%)|
|VC||10 (39%)||8 (31%)||5 (19%)||1 (4%)||2 (8%)|
|SCC-VF||7 (41%)||6 (35%)||2 (12%)||0||2 (12%)|
|SCC-VC||4 (67%)||1 (17%)||0||1 (17%)||0|