A dysfunctional or downregulated DNA mismatch repair system can result in accumulation of DNA insertions and deletions that ultimately lead to a high mutational burden.41 One or more of the genes involved in DNA mismatch repair are often found to be mutated in colorectal cancer, which results in microsatellite instability (MSI), characterized by a high mutational burden.41 We found that ADP-heptose downregulated two out of these four genes, MSH2 and PMS2. This evidence concerns the gene PMS2 and colorectal cancer.