Scientists have developed a tiny antibody that can find a common cancer protein and light up tumors during PET scans. In tests with mice, tumors containing the EphA2 protein glowed brightly after using this antibody. This method could help doctors quickly identify patients suitable for new targeted cancer treatments. It represents a faster and less invasive alternative to traditional tissue testing. The antibody targets the EphA2 protein, which is present in tumors. Tests were successfully performed on mouse models with these tumors.