Basic principles of cancer genetics

All cancer can be described as genetic, that is, due to altered DNA. Many of these mutations will be accumulated during the normal division of cells. However, some people may inherit abnormal genes, which predispose those individuals to high risk of certain malignancies. These individuals can sometimes be identified as having a family history of affected individuals, some of which might have early age of onset or multiple malignancies. Specific genes have been identified as being associated with certain of these malignancies. The hereditary cancers include (but are not limited to) ovary, breast, colon, endometrium, and to a lesser extent, prostate, skin and pancreas. Some of these cancer predisposing genes are highly penetrant with up to 80 to 90 percent of gene carriers developing the associated malignancy within a 70 year life expectancy. Molecular testing for the presence of cancer predisposing genes is available for many of the hereditary syndromes. While there currently is no way to correct a mutant gene, early detection and some techniques of chemoprevention are of clinical value. People who fear that they are at high risk only learn that they are not, can benefit from the relief of anxiety through the genetic counseling process.