Two widely used tests to analyze the genetics of tumors often don't come to the same conclusions, according to head-to-head analyses. Authors of two recent studies comparing these tests say doctors need to be careful not to assume that these tests are providing a complete picture of a tumor's genetic variants, when using them to select treatments for cancer patients. Dr. C. Anthony "Tony" Blau and colleagues at the University of Washington School of Medicine in Seattle compared results from two commonly used tests that are used to identify mutations in tumors. The FoundationOne test is used on tissue samples extracted from tumors. Guardant360 gathers traces of tumor DNA from blood samples.... http://www.npr.org/sections/health-shots/2016/12/16/505864740/when-genetic-tests-disagree-about-best-option-for-cancer-treatment?