MLH1 and colorectal carcinoma: BRAF mutation is tightly associated with MSI-H and MLH1 methylation in Western CRC populations [31, 42], but the main reason of MSI-H (6.1%, 5/82) and MLH1 methylation (3.7%, 15/401) in Chinese CRC populations remains unclear due to very low incidences of BRAF mutation.