MRC1 and mismatch repair cancer syndrome 1: Another predictive biomarker in colorectal adenocarcinoma is the alteration of the DNA mismatch repair (MMR) [55,56], that can be identified through immunohistochemistry for MMR proteins (MLH1, PMS2, MSH2 and MSH6) and through the detection of MSI (which is a consequence of MMR deficiency) [52].