In the mid-1970s, the American microbiologists John Michael Bishop and Harold Varmus tested the theory that healthy body cells contain dormant viral oncogenes that, when triggered, cause cancer. They showed that oncogenes are actually derived from normal genes (proto-oncogenes) present in the body cells of their host.

Where are oncogenes found in the cell?

Cellular oncogenes are highly conserved in vertebrate species, and the K-ras-2 locus, which has been characterized in both humans and mice, has been located to the centromere area of the rabbit chromosome 16 by use of the labeled human cDNA probe (Martin-DeLeon and Picciano, 1988).

What is an oncogene and how does it cause cancer?

An oncogene is any gene that causes cancer. One of the main characteristics of cancer is uncontrolled cell growth. Because proto-oncogenes are involved in the process of cell growth, they can turn into oncogenes when a mutation (error) permanently activates the gene.