Mini‑Circles Make Cancer Easy to Spot in Blood and Urine

Scientists have created tiny DNA loops that turn on only when they meet cancer cells. These loops, called minicircles, are built with a special design that keeps them stable and lets them stay in the body for a long time. When cancer is present, the loops become active and release signals that can be detected in a simple blood or urine test. The new system uses two different markers inside each minicircle. One marker reacts to a chemical that is common in many tumors, while the other responds to an enzyme that cancer cells overproduce. Because both markers must be triggered, the test becomes more accurate and reduces false positives. To keep the minicircles from breaking apart, researchers added a scaffold/matrix attachment region motif. This part acts like a safety net, holding the DNA in shape and allowing it to survive the harsh environment of the bloodstream. The result is a sensitive tool that can pick up even very low levels of cancer markers.The team tested the approach in animal models. They found that the minicircles stayed active for several days, giving doctors a larger window to detect disease. Moreover, the test could be repeated without harming the animal, showing promise for regular monitoring in patients. Beyond cancer detection, this technology could be adapted to track other diseases that produce specific chemicals or enzymes. By swapping the markers, researchers can tailor the minicircles to new targets while keeping the stable backbone unchanged. Overall, the work demonstrates how clever DNA engineering can turn a complex biological problem into a simple, repeatable test. It offers hope for earlier diagnosis and better patient outcomes.