HPV infection and p16 expression in carcinomas of the minor salivary glands.

The correlation between p16 upregulation and high-risk HPV infection is well known in head and neck squamous cell cancer. However, no information is available on rare carcinomas of the minor salivary glands. We analyzed 38 samples of minor salivary gland malignancies. p16 expression was determined by immunohistochemistry, HPV DNA by using in situ hybridization to detect low (type 6 and 11) and high (type 16 and 18) risk HPV types. In 71% of samples p16 expression was found. Low-risk HPV DNA could not be detected in any of the samples, whereas high-risk HPV DNA was found in two samples of mucoepidermoid carcinoma, which also showed the highest immunoreactivity with p16. HPV infection does not seem to be a common event in minor salivary gland carcinoma. Upregulation of p16 is present in the majority of cases but only diffuse staining correlates with HPV 16 and 18 infections.