Normally, p53 monitors cell division. When division has errors, p53 arrests the cell at the G1, or first growth phase, of the cycle, until the errors are corrected, and if they can't be corrected, p53 destroys the cell by apoptosis. The DNA for p53 is found on the chromosome location 17p13, and the protein it produces is active in the cell nucleus. I started out writing about individual genes. Now as I understand it better, I write about the next higher level of organization, cascades .
Cascades are a sequence of steps.
Each step is usually controlled by a gene and an enzyme. AKT is an oncogene. PI3 is the accelerator, PTEN is the brake. These cascades can get very complicated, and begin to resemble Rube Goldberg cartoons . For a more comprehensive background, the standard textbooks are Campbell's Urology and DeVita's Cancer.