The Route to HPV-Associated Neoplastic Transformation: A Review of the Literature

Human papillomaviruses (HPVs)-small, nonenveloped viruses with double-stranded circular DNA-are believed to have a role in the progression of cancer. However, the exact mechanisms are not well established. The interference of HPV proteins, especially E6 and E7, in the cell cycle is considered to be the main pathway. It is still questioned whether the expression of these proteins or the viral load is more important in neoplastic transformation. Furthermore, HPV is believed to adapt mechanisms to evade the host cell immune system; persistent HPV infection may also play a role in oncogenic transformation by causing genomic instability and local immune suppression. These factors may cause accumulation of genomic alterations within the host cell and integration of the viral genome into the host genome. In recent years, epigenetic modifications, such as methylation, have also been considered to take part in neoplastic transformation. All of these alterations to the genome may be favorable to the development of cancer. This article highlights the association of HPV in neoplastic transformation and cancer progression.