High-risk human papillomaviruses and epstein-barr virus presence and crosstalk in human oral carcinogenesis

Oral cancer is the most frequent type of malignancy of the head and neck area worldwide. This cancer is a major cause of mortality in several parts of the world especially in certain Asian countries. In fact, the majority of cancer deaths are the result of metastasis, either directly due to tumor involvement of critical organs or indirectly due to therapeutic side effects. On the other hand, it is estimated that 10–20% of human cancers are linked to virus infections including Epstein-Barr virus (EBV) and high-risk human papillomaviruses (HPVs) especially types 16, 18, and 33, which cumulatively infect 80–90% of the population worldwide. Moreover, it has been reported that oncoproteins of high-risk HPV type 16 can covert noninvasive and nonmetastatic human cancer cells into invasive and metastatic form. It was pointed out that high-risk HPVs and EBV are important etiological factors in human oral cancer, since around 35 and 55% of these cancers are positive for these viruses, respectively. In addition, it was recently revealed that high-risk HPVs and EBV can be copresent in human oral cancer, and their copresence is associated with high-grade invasive carcinomas. Thus, it is evident that high-risk HPVs and EBV oncoproteins play an important role in the initiation and progression of human oral cancer. In this chapter, we will overview the presence and role of HPVs and EBV in this frequent malignancy, more specifically; we will focus on the role of their oncoproteins and their interactions with other oncogenes in human oral carcinogenesis.Scopu