The objectives of the study were to investigate the expression of p16 and the presence of HR-HPV in OSCC and oral verrucous carcinoma (VC) and to determine if p16 could be used as a surrogate marker for HR-HPV.
Diffuse p16 expression was associated with younger age at presentation (P<0.0001), basaloid and warty carcinoma subtypes (P<0.0001), and usual vulvar intraepithelial neoplasia (P<0.0001) and was negatively associated with p53 immunopositivity (P=0.0008).
β-PV DNA was detected in 5/30 VC (16.7%) and in 18/30 normal tissue samples (60.0%): HPV-19, -24 and -36 were identified in VC, and HPV-5, -9, -12, -23, -24, -38, -47, -49 and -96 in normal tissue, whereas HPV type was not determined in 2/5 cases of VC and in 6/18 normal tissue samples. p16 expression was detected in a subset of samples and was higher in VC than in normal tissue.
Promoter hypermethylation status of p16 and MGMT genes were examined by the methylation-specific PCR (MSP) in OSCC (n = 51), verrucous carcinoma (n = 2), and carcinoma in situ (n = 2) tissues.
The high immunohistochemical expression for both p16 and pRb in VC is quite different compared with SCC, which may indicate a possible relationship between VC and human papillomavirus (HPV) infection.