What are oncogenic viruses Slideshare?
• Oncogenic viruses • Oncogenesis is the result of genetic changes that alter the expression or function of proteins that play critical roles in the control of cell growth and division • •Oncogenic viruses cause cancer by inducing changes that affect cell growth and division 10/6/2012 Dr.T.V.Rao MD 20.
What viruses are oncogenic?
Oncogenic DNA viruses include EBV, hepatitis B virus (HBV), human papillomavirus (HPV), human herpesvirus-8 (HHV-8), and Merkel cell polyomavirus (MCPyV). Oncogenic RNA viruses include, hepatitis C virus (HCV) and human T-cell lymphotropic virus-1 (HTLV-1).
What is meant by oncogenic virus?
During the viral replication process, certain virus’s DNA or RNA affects the host cell’s genes in ways that may cause it to become cancerous. These viruses are known as oncogenic viruses, meaning viruses that cause or give rise to tumors.
Do viruses have oncogenes?
Viruses. Viral oncogenes participate in carcinogenesis by the RNA of the viral genome being transcribed into the DNA genome of the host by the enzyme reverse transcriptase.
Do all retroviruses have oncogenes?
Oncogenes are genes that cause cancer. Retroviruses contain oncogenes and cause cancer in animals and, perhaps, in man. The viruses have appropriated their oncogenes from normal cellular DNA by genetic recombination.
Are oncogenic viruses retroviruses?
What do oncogenic viruses have in common?
Human oncogenic viruses have diverse genomes, cellular tropisms, cancer pathologies and disease prevalence (Table 1). However, they share many features that can lead to cancer in humans. They are transmitted between humans and can establish chronic infections that last for years without obvious symptoms.
How does oncogenic virus work?
Human oncogenic viruses modulate signal transduction pathways that control cell growth, proliferation and survival to optimize cellular conditions for viral replication, virion assembly and autophagic evasion in the absence of growth or survival signals.
Is hsv1 oncogenic?
All human herpesviruses (HHVs) have been implicated in immune system evasion and suppression. Moreover, two HHV family members, i.e. EBV and KSHV, are recognised as oncogenic viruses. Our literature review summarises additional examples of possible oncogenic mechanisms that have been attributed to other HHVs.
What is proto-oncogene and tumor suppressor gene?
A proto-oncogene is a segment of DNA that codes for one of the positive cell cycle regulators. If that gene becomes mutated so that it produces a hyperactivated protein product, it is considered an oncogene. A tumor suppressor gene is a segment of DNA that codes for one of the negative cell cycle regulators.
Do proto-oncogenes suppress tumor growth?
Proto-oncogenes promote cell growth. When changed or mutated, they become oncogenes. They can then promote tumor formation or growth.