Can a single dose of the human papilloma virus (HPV) vaccine prevent oropharyngeal cancer?

Role of Epstein-Barr Virus and Human Papilloma Virus in the Development of Oropharyngeal Cancer: A Literature Review

The aim of this review was to describe the association and related mechanisms between HPV, EBV, and the development of oral and oropharyngeal cancer. A search for scientific evidence was carried out in electronic databases (MEDLINE/PubMed, SciELO). It was found that, among the carcinogenic mechanisms of HPV, E6 and E7 proteins are responsible for the malignization process, inhibiting tumor suppressors p53 and pRb. As to EBV, it was noted that its “hit and run” phenomenon manipulates the host epigenetic mechanism, triggering the tumor process without the virus being currently present; a “cellular reprogramming” is essentially generated, causing heritable changes in gene expression without DNA mutation. In conclusion, there is an association between oropharyngeal carcinogenesis and HPV and also between the former and EBV. Further studies are required to clarify the causal mechanisms and impact of both viruses on cancer development and to obtain biomarkers of greater specificity in the case of EBV.

Human Papillomavirus Vaccine to End Oropharyngeal Cancer. A Systematic Review and Meta-Analysis

ABSTRACT

Oropharyngeal cancer (OPC) is currently the most frequent human papillomavirus (HPV)-related malignancy in high-income countries. Oral HPV16 infection is the cause of HPV-related OPC in more than 90% of cases and is primarily (90%) linked to oral sex. This systematic review and meta-analysis aimed at comparing the prevalence of oral vaccine-type HPV infection in individuals vaccinated with HPV vaccines and unvaccinated controls. Three databases (MEDLINE, ScienceDirect, and the Cochrane Library), as well as other sources, were searched by 2 independent reviewers. Controlled studies testing the efficacy or effectiveness of licensed HPV vaccines were included. The primary end point was multiple oral HPV infections in one individual with low-risk and high-risk types. Secondary end point was the number of oral HPV16 infections. Six studies-2 randomized controlled trials and 4 cross-sectional studies-with a total of 15,240 participants were included in a meta-analysis, which showed that vaccinated individuals were 46% (risk ratio, 0.54; 95% confidence interval, 0.32-0.91) less likely to develop oral vaccine-type HPV infection (P = 0.02). A second meta-analysis of 4 studies (1 randomized controlled trial and 3 cross-sectional studies) and 13.285 participants showed 80% (risk ratio, 0.20; 95% confidence interval, 0.09-0.43) less likelihood of oral HPV16 infection (P < 0.0001). This study suggests that HPV vaccines can protect against oral vaccine-type HPV infection including high-risk HPV16 infection, thus reducing the incidence of HPV-related OPC. Vaccination against HPV, especially in males, who are predominantly affected by HPV-related OPC, could result in the prevention of this disease.