MRC1 and colorectal carcinoma: Interestingly, about 45% of MMR-proficient and 65% of MMR-deficient CRC had a high immunoscore, while 55% of MMR-proficient and 35% of MMR-deficient CRC had a low immunoscore, suggesting that some of the MMR-deficient tumors are unable to mount an antitumor response while the reverse may apply for some of the MMR-proficient population10.