Tumor viruses, Oncogenesis and human cancers: Host-Virus interactions
Tumor viruses, Oncogenesis and human cancers: Host-Virus interactions
Piruz Shadbash,1Seyed Reza Mohebbi,2,*Seyed Masoud Hosseini,3Seyed Amirmohammad Seyed Mirzajani,4Shabnam Kazemian,5Hamid Asadzadeh-Aghdaei,6
1. Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences 2. Research Center for Gastroenterology and Liver Diseases, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran 3. Department of Microbiology and Microbial Biotechnology, Faculty of Life Sciences and Biotechnology, Shahid Beheshti University, Tehran, Iran 4. Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences 5. Research Center for Gastroenterology and Liver Diseases, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran 6. Basic and Molecular Epidemiology of Gastrointestinal Disorders Research Center, Research Institute for Gastroenterology and Liver Diseases, Shahid Beheshti University of Medical Sciences, Tehran, Iran
Introduction: Tumor viruses or oncogenic viruses are viral agents capable of causing cancer. Since the first understanding of Retroviruses in the 1950-1960s, the term of Oncoviruses has been used to indicate the characteristics of these RNA viruses. The main viruses related to human cancers are the human papillomavirus (HPV), the hepatitis B and hepatitis C viruses (HBV and HCV), the Epstein-Barr virus (EBV), the human T-lymphotropic virus (HTLV), the Kaposi sarcoma-related herpesvirus (KSHV) and Merkel cell polyomavirus (MCPyV).
Methods: They seem to be the second most important risk factor for cancer development in humans. It seems that the majority of human and animal viruses do not cause cancer, likely due to the long-term evolution between the virus and its host. Studying the Oncoviruses is crucial for a better understanding of cell cycle control mechanisms and relevant host genes such as retinoblastoma.
Results: In 2002, the world health organization International Agency for Research on Cancer estimated that infections stimulated around 17% of human cancers, from this about 11.9% caused by one of these seven viruses. A recent study of 2658 samples from 38 different types of cancers has revealed that 16% of cancers possibly originated from a virus.
Conclusion: These cancers can be prevented via vaccination, precise screening, on-time diagnosis using proper tests, and treatment. Mechanisms of viral carcinogenesis consist of generating genomic instability, increasing the rate of uncontrolled cell proliferation, resistance to apoptosis, constant inflammation, alterations in DNA repair mechanisms, and alteration of cell polarity, which often coexist with evasion mechanisms of the antiviral immune response.