Is there enough benefit to justify sequencing all patients’ tumors? Yes.

A fundamental premise of oncology—indeed of all medicine—is that every disease, even an untreatable one, warrants a diagnosis. The light microscope, invented in the 1500s, is still used to diagnose cancer. Peering at the surface of cells to determine their tissue of origin renders a diagnosis. However, if we are to improve our ability to treat and defeat cancer, we must supplement this centuries-old technology with the “molecular microscope.” Genomic testing permits interrogation of the inside of the cell and definition of a tumor’s precise coding sequence. Genomics is the diagnosis, and the most powerful argument for its universal use is that every patient afflicted with cancer deserves a diagnosis.