Expression of Human Papillomavirus and the p16 Gene in Oral Potentially Malignant Disorders (OPMD): a Comparative Study With Oral Squamous Cell Carcinoma

BACKGROUND: The incidence of oral squamous cell carcinoma (OSCC) of the tongue is increasing in the younger population without traditional risk habits that lead researchers to find other related factors such as diet and viruses, especially human papillomavirus (HPV). It is noteworthy that many OSCCs develop from oral potentially malignant disorders (OPMDs). Correct diagnosis and timely management of OPMDs may help to prevent malignant transformation, and therefore it is worth seeing the involvement of HPV in OPMDs and oral cancers, as the preventive and curative measures in HPV-induced cancer types are different from the conventional types of OPMDs and OSCCs. Therefore, the main objective of this study was to identify a relationship between HPV and p16 in OPMDs and compare it with OSCC.

METHODS: This study was conducted on 83 cases of known OSCCs and OPMDs (oral submucous fibrosis, leukoplakia, and oral lichen planus). Assays, such as polymerized chain reaction (PCR) and reverse transcription-PCR, were carried out for HPV and p16 . The results were compared with clinical information and with the literature. The results were analyzed using SPSS 16.0 for windows.

RESULTS: P16 expression was mostly seen in males than in female patients. Out of 21 cases of keratosis with dysplasia, 19% expressed p16 . Of 26 oral lichen planus patients, 29% showed the p16 gene with immunohistochemistry. Interestingly, a high percentage of OSF cases expressed p16 (48.27%). Minimal expression was observed in OSCC (6.25%). HPV DNA was detected in 2.4% of the total sample. Both p16 and HPV were detected in a single case of OSCC. OPMDs expressed a significant amount of the p16 gene by immunohistochemistry and reverse transcription-PCR technique when compared with malignant lesions, suggesting a possible inactivation of the p16 gene. HPV and p16 are mostly negative in our OSCC sample, exhibiting low prevalence.

CONCLUSIONS: OPMDs expressed a significant amount of the p16 gene when compared with malignant lesions, suggesting a possible inactivation of the p16 gene. Although OSF expressed p16 , HPV was not detected, suggesting that over-expression could be independent of HPV. OSCC shows low HPV prevalence.