Cancer
Retroviruses that cause tumor growth include Rous sarcoma virus and mouse mammary tumor virus. Cancer can be triggered by proto-oncogenes that were mistakenly incorporated into proviral DNA or by the disruption of cellular proto-oncogenes. Rous sarcoma virus contains the src gene that triggers tumor formation. Later it was found that a similar gene in cells is involved in cell signaling, which was most likely excised with the proviral DNA. Nontransforming viruses can randomly insert their DNA into proto-oncogenes, disrupting the expression of proteins that regulate the cell cycle. The promoter of the provirus DNA can also cause over expression of regulatory genes.
Read more about this topic: Retrovirus
Famous quotes containing the word cancer:
“The same people who tell us that smoking doesn’t cause cancer are now telling us that advertising cigarettes doesn’t cause smoking.”
—Ellen Goodman (b. 1941)
“Madness is locked beneath. It goes into tissues, is swallowed by the cells. The cells go mad. Cancer is their flag. Cancer is the growth of madness denied.”
—Norman Mailer (b. 1923)
“I wish more and more that health were studied half as much as disease is. Why, with all the endowment of research against cancer is no study made of those who are free from cancer? Why not inquire what foods they eat, what habits of body and mind they cultivate? And why never study animals in health and natural surroundings? why always sickened and in an environment of strangeness and artificiality?”
—Sarah N. Cleghorn (1976–1959)