[Human Oncogenic Viruses: Old Facts and New Hypotheses].

Numerous studies on the nature of neoplastic growth have demonstrated that oncogenic viruses maybe one of the factors causing cancer. According to various estimates, 10-20% of all human cancers are caused by viruses. For example, the Epstein-Barr virus (EBV), hepatitis B and C viruses, human papillomavirus (HPV), human T-lymphotropic virus type 1 (HTLV-1), human herpesvirus type 8 (HHV-8), and Merkel cell polyomavirus were implicated in initiating tumors. At the same time, the long period between viral infection and the manifestation of cancer significantly complicates the search for a causal relationship between the presence of a virus in the human organism and the malignant transformation. For this reason, the role of certain viruses in the initiation of neoplastic processes in humans remains an unresolved issue.