Interestingly, it was reported that monoallelic MYH, one of BER genes, germline mutations showed a negative correlation with MSI in colorectal cancer patients.22 It was also reported that BER deficiency was rarely accompanied by CIN (Chromosomal instability) or MSI.23 Another study showed that MLH1 −93G>A polymorphism was associated with an increased risk of MSI-H colorectal cancer.24 Thus, we investigated whether MSI might be associated with hOGG1 Ser326Cys polymorphism in colorectal cancers and found no significant result. Here, MLH1 is linked to hyperinsulinemic hypoglycemia, familial, 4.