MLH1 is deficient in a high proportion of patients with microsatellite instability (MSI-H). It has been
shown that immunohistochemical analysis of MLH1 expression is a practical and reliable method
for the routine detection of the vast majority of colorectal carcinomas with high-frequency MSI,
which are frequently identified in hereditary nonpolyposis cancer (HNPCC) and are account for
15% of sporadic colorectal cancer. MLH1 negative tumors maybe associated with a longer
1. Bronner CE, et al. Nature. 1994 Mar 17;368(6468):258-10
2. Lanza G, et al. Mod Pathol. 2002 Jul;15(7):741-9.
3. Marcus VA, et al. Am J Surg Pathol. 1999 Oct;23(10):1248-055.