MSI was prominently demonstrated in hereditary non-polyposis colorectal cancer (HNPCC) and has been associated with defects in certain DNA repair genes.[63][64] Conservation of genomic stability is at least partially dependent on a specific class of DNA mismatch repair (MMR) genes which are responsible for correcting the misincorporated nucleotides caused by either a replication error or any chemical induction.[65] Structural and functional defects of MMR genes lead to the loss of MMR proteins, down-regulation of MMR enzyme activity, and a lower expression of MMR-related genes. Here, MRC1 is linked to hereditary nonpolyposis colon cancer.