MHC CLASS I LOSS AND CANCER IMMUNE ESCAPE

Most tumor cells derive from MHC-I-positive normal counterparts and remain positive at early stages of tumor development. T lymphocytes can infiltrate tumor tissue, recognize and destroy MHC class I (MHC-I) positive cancer cells (“permissive” phase I). This phase end in the total destruction of the tumor with no clinical evidence. Alternatively, MHC-I-negative tumor cell variants resistant to T-cell killing can emerge. During this process of T cell imm