High Quality Content by WIKIPEDIA articles! Cancer is a genetic disorder in which the normal control of cell growth is lost. Cancer genetics is now one of the fastest expanding medical specialties. At the molecular level, cancer is caused by mutation(s) in DNA, which result in aberrant cell proliferation. Most of these mutations are acquired and occur in somatic cells. However, some people inherit mutation(s) in the germline. The mutation(s) occur in two classes of cellular genes: oncogenes and tumor suppressor genes.