Molecular mechanisms underlying human papillomavirus E6 and E7 oncoprotein-induced cell transformation

Human papillomaviruses (HPVs) are the causative agents of 5% of all human cancers, with cervical cancer being the most important. Two viral oncoproteins, E6 and E7, are essential for the development and maintenance of malignancy. Both proteins function by targeting critical pathways that are essential for maintaining cellular homeostasis. As a consequence of these activities, this produces an environment that is favourable for the normal viral life cycle, but when perturbed, can result in the initiation of changes to the host cell, which ultimately results in the development of a malignancy. In this review we discuss the role of these different functions of the viral oncoproteins during the viral life cycle and carcinogenesis, with an emphasis on how induction of DNA damage by the viral oncoproteins, in conjunction with the stem like nature of the target cells, can ultimately result in the development of cancer.