Understanding Tumor Suppressor Genes
Tumor suppressor genes are genes that have the power to stop (or suppress) tumors from forming. They do that by preventing cells from dividing uncontrollably. There are many of these kinds of genes in the human DNA.
Normally people inherit two working copies of these cancer-protector genes. They get one from each parent. Sometimes, though, a person inherits only one working copy. If that gene stops working, the person is more at risk for cancer.