In short, p53 is a tumor-suppressor protein that arrests the cell cycle and prevents cell growth and survival when DNA damage occurs.Thus, inactivation of p53 by E6 can promote unregulated cell division, cell growth, and cell survival, characteristics of cancer.Such infections are associated with genital or anal warts (medically known as condylomata acuminata or venereal warts), and these warts are the most easily recognized sign of genital HPV infection.The strains of HPV that can cause genital warts are usually different from those that cause warts on other parts of the body, such as the hands or feet, or even the inner thighs.
p53 also upregulates the p21 protein, which blocks the formation of the cyclin D/Cdk4 complex, thereby preventing the phosphorylation of RB, and in turn, halting cell cycle progression by preventing the activation of E2F.
Studies have also shown a link between a wide range of HPV types and squamous cell carcinoma of the skin.
In such cases, in vitro studies suggest that the E6 protein of the HPV virus may inhibit apoptosis induced by ultraviolet light.
The great majority of genital HPV infections never cause any overt symptoms and are cleared by the immune system in a matter of months.
Moreover, people may transmit the virus to others even if they do not display overt symptoms of infection.