2.The first human oncovirus was discovered in 1964. Today, a \"tumor virus\" or
ID: 212924 • Letter: 2
Question
2.The first human oncovirus was discovered in 1964. Today, a "tumor virus" or "cancer virus" is any virus with a DNA or RNA genome that can cause cancer. Hence, they are classified as either "DNA oncovirus" or "RNA oncovirus". Research them, then choose one. Using no more than two paragraphs (1/2 page max, single-spaced), briefly explain the basic mechanisms of action by which the virus you chose causes cancer (you may refer to lecture slides at the end of L15, but make sure that your search goes beyond that). Cite your source of information at the end of your answer.Explanation / Answer
Human papillomavirus (HPV) is associated with pathogenesis if several cancer types especially cervical cancer. It is also associated with oral, penile, vulvar and anal cancer. Although there are about 130 types of HPV, only a subset are considered “high-Risk.” This is a DNA virus, which invades the cells by erosion of cell layers to reach the stem cells. The viral DNA is integrated into the host cell’s genome. The E7 viral protein degrades the retinoblastoma and thus affects cell cycle progression. The E6 viral protein forms a complex with ubiquitin ligase, which causes degradation of p53. Both the E6 and E7 viral proteins target telomerase and DNA damage repair pathways and induce genomic instability.
HPV vaccination is available, which helps to prevent colon cancer caused by this organism. Disadvantages of vaccines generally associate with the vaccine failure and the virulence factors. Vaccines cannot cure or treat the already established cancer. Surgical removal of the tumor followed by a combination of chemotherapy and radiation therapy are used in the treatment of established cancers. Chemotherapy may also be used before surgery to shrink the tumor.
Reference:
Münger, K., Baldwin, A., Edwards, K. M., Hayakawa, H., Nguyen, C. L., Owens, M., ... & Huh, K. (2004). Mechanisms of human papillomavirus-induced oncogenesis. Journal of virology, 78(21), 11451-11460.
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