Classifying cancer tumors by their molecular structure rather than the tissue or organ where they were found, such as the breast or bladder, may lead to more accurate diagnoses and potentially better treatments and outcomes for patients, a new study finds. In the largest undertaking to analyze and compare different cancer types based on genomic sequencing, researchers found at least 10 percent of tumors - and possibly as high as 30 to 50 percent - would be identified differently if oncologists determined their diagnoses by a tumor's molecular makeup. "The old system classifying cancer by the tissue of where it...