This article gives a good summary of the use of genetic tests to indicate your risk of developing certain cancers, as well as the down sides of genetic testing.
Genetic tests can determine whether you are at risk of developing cancer by finding mutations in a person’s genes. The risk of developing cancer increases if you have a genetic predisposition or susceptibility to cancer. Approximately 5% to 10% of all cancers are related to an inherited gene mutation. They may help provide an early diagnosis and peace of mind. However, genetic testing can’t detect all gene mutations, may provide false negative results, and can result in increased anxiety and high medical costs.