Objective: The aim of this study was to evaluate cases of oral epithelial dysplasia for biologically significant human papillomavirus (HPV) infection.
Study design: Forty consecutive cases of high-grade dysplasia and 37 cases of low-grade dysplasia were examined for p16(INK4a) expression by immunohistochemistry. High-risk HPV infection was assessed in p16-positive cases using in situ hybridization. Proliferation index was assessed with MIB-1 immunohistochemistry.
Results: Eleven of 40 high-grade dysplasias and one of 37 low-grade dysplasias were p16 positive. High-risk HPV was detected in seven cases of p16-positive high-grade dysplasia. The difference between high- and low-grade dysplasia was statistically significant (P = .01). HPV-positive high-grade dysplasias showed a distinctive histologic appearance and MIB-1 labeling pattern. Most high-risk HPV-positive cases were seen in the floor of mouth.
Conclusion: High-risk HPV was associated with a subset of cases of severe epithelial dysplasia/carcinoma in situ that demonstrated diffuse loss of squamous differentiation and a high proliferation index.
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