While identifying cancer types is key to proper treatment, this can be difficult once tumors have spread. Each year, more than 400,000 people in the U.S. have cancers that spread, and the diagnosis is uncertain in about 30% of them. Now, more people will have access to a test that classifies tumors based on the expression of 92 genes. Called CancerTYPE ID, the test will be used by Mayo Medical Laboratories, which serves the Mayo Clinic as well as more than 5,000 other hospitals worldwide. The test can distinguish more than 50 types of cancer, including tumors that are easily confused, such as breast, cervical, endometrial, and ovarian.