Carcinogenesis: Role of Viruses in Pathogenesis of Cancers

Nowadays، plague and cholera are not major concerns for human society، but cancer is the biggest concern، affecting thousands of people worldwide. Therefore، many cancer studies are performed each year، investigating mechanisms and agents involved in the pathogenesis of different cancers، and seeking new therapeutic approaches to effectively treat them. Every day a new unknown fact is revealed about the factors involved in cancer. In the past، it was assumed that the only physical and chemical factors cause cancers; however، nowadays there are new attitudes that indicate the direct or indirect involvement of biological factors، especially viruses، in the pathogenesis of cancers. Until now، the direct role of six viruses including hepatitis B، hepatitis C، human papilloma virus، human T-lymphotropic virus Type 1، Epstein-Barr and human herpes virus 8، and also the indirect role of human immunodeficiency virus (HIV) have been proven by scientists. In the present manuscript، we attempted to review the current information about the role of above-mentioned viruses in pathogenesis of some cancers.