During this complex process, mistakes may occur. Mismatch-repair genes are the DNA repair genes that correct these naturally occurring spelling errors in the DNA. When these genes are altered or mutated, however, mistakes in the DNA remain. If these mistakes occur in tumor suppressor genes or proto-ocnogenes, eventually this will lead to uncontrolled cell growth and tumor formation. There are other types of DNA repair genes that repair errors in DNA that occur from mutagenic agents such as large doses of radiation. Mutations in DNA repair genes can be inherited from a parent or acquired over time as the result of aging and environmental exposures. DNA repair genes require two mutations ( both members of the gene pair) in order for the process of tumor formation to occur. It takes mutations in several of these genes for cancer to develop. In most cases of cancer, all the mutations are acquired. In inherited cancer, one mutation is passed down from the parent, but the remainder are required. Since it takes more than a single mutation to cause cancer, not all people who inherit a mutation in a tumor suppressor gene, proto-ocnogene, or DNA repair gene will develop
During this complex process, mistakes may occur. Mismatch-repair genes are the DNA repair genes that correct these naturally occurring spelling errors in the DNA. When these genes are altered or mutated, however, mistakes in the DNA remain. If these mistakes occur in tumor suppressor genes or proto-ocnogenes, eventually this will lead to uncontrolled cell growth and tumor formation. There are other types of DNA repair genes that repair errors in DNA that occur from mutagenic agents such as large doses of radiation. Mutations in DNA repair genes can be inherited from a parent or acquired over time as the result of aging and environmental exposures. DNA repair genes require two mutations ( both members of the gene pair) in order for the process of tumor formation to occur. It takes mutations in several of these genes for cancer to develop. In most cases of cancer, all the mutations are acquired. In inherited cancer, one mutation is passed down from the parent, but the remainder are required. Since it takes more than a single mutation to cause cancer, not all people who inherit a mutation in a tumor suppressor gene, proto-ocnogene, or DNA repair gene will develop