A new type of cancer test can tell whether — and when — a tumor is coming back after initial treatment. The test uses a sample of the original tumor to identify unique cancer gene sequences. Later blood tests look for that genetic signature and tell whether surgeons removed the entire tumor, whether the cancer has spread to other parts of the body, or whether the cancer is coming back. It’s the brainchild of a team of Johns Hopkins researchers led by Victor E. Velculescu, MD, PhD. The team initially hoped to find markers that would identify cancers in any patient. Instead, they found that every patient’s cancer is unique. But that uniqueness turned out to be the key to a new tool that may revolutionize cancer care. ‘A person’s cancer is as individual as a fingerprint,’ study researcher Luis Diaz, MD, said at a news conference. ‘[The test] can clearly detect cancer in patients and monitor the burden of disease and response to treatment.’ Previous efforts to fingerprint tumors relied on sequencing each letter in the cancer’s genetic code. Even with modern genetic tools, that’s a formidable task. Velculescu’s team had a better idea. […]