text_1: Testing for more breast cancer genes offers useful information
text_2: This story does a nice job of describing a recent study that looked at the clinical validity of several cancer genetic test panels. The study looked at a group of women who were very high risk for breast cancer but tested negative for the BRCA1/2 genes and who were tested for other, potentially high-risk genes. It describes the potential harms associated with such test panels, touches on the authors’ reported conflicts of interest, and avoids disease mongering. It could have done better by specifying costs, interviewing independent experts, and by putting this evidence in context — explaining some general issues with genetic testing and their analytical as well as clinical validity. About 5-10% of breast cancer cases in the US are linked to hereditary genetic mutations, the two best-known mutations being BRCA1 and BRCA2. Mutations in dozens of other genes have been studied and identified as possible risk factors for breast cancer. Myriad Genetics owned a patent on these two tests until 2013, when the Supreme Court ruled that genes couldn’t be patented, thus invalidating their patents and their status as the only company that could offer BRCA1/2 genetic testing. Since this ruling, other companies have begun to offer multiple genetic test panels that are now marketed to doctors and to patients alike. The main question behind these, and other (including non-cancer), genetic tests is what to do with the information generated by them. Are identified genetic mutations “clinically actionable”? Are the results meaningful enough to allow the medical team to alter or tailor clinical management? The availability of various panels of genetic tests, for cancer as well as for other diseases, has been controversial in the medical community. At issue are the “analytical validity” of the test (Can the test accurately detect whether a specific genetic variant is present or absent? ), as well as the “clinical validity” of the test (Can the test provide information about diagnosis, treatment, management, or prevention of a disease that will be helpful to a patient or to a consumer?)