The need to distinguish between normal cells and tumor cells is a feature that has been long sought for most types of cancer drugs. Tumor antigens, unique proteins on the surface of a tumor, are potential targets for a normal immune response against cancer. Identifying which antigens a patient’s tumor cells express is the cornerstone of designing cancer therapy for that individual. But some of these tumor antigens are also expressed on normal cells, inching personalized therapy back to the original problem.
