In sporadic MSI cases of colon cancer this mutation is found in proximal colon tumors with MLH1 methylation (80% of cases), while in tumors from hereditary nonpolyposis colorectal cancer (HNPCC) cases with MLH1, MSH2 or MSH6 germline mutations, no BRAF mutations are detected. Here, MSH2 is linked to hereditary nonpolyposis colon cancer.