A region at the edge of colorectal tumors where cancer cells directly contact fat tissue — called SARIFA — has emerged as a powerful signal of how dangerous a tumor may be. Studying nearly 1,900 patients across two independent groups, researchers found that tumors with SARIFA present were significantly more likely to result in cancer-related death, with roughly twice the risk compared to tumors without it. SARIFA-positive tumors also showed fewer immune cells capable of fighting cancer and more immune cells that actually help the tumor grow and evade the body’s defenses. Because SARIFA can be reliably identified by pathologists under a microscope, it holds promise as a practical tool to better identify colorectal cancer patients who may need more aggressive treatment.