Bethesda Guidelines: Relation to Microsatellite Instability and <i>MLH1</i> Promoter Methylation in Patients with Colorectal Cancer

Abstract

The Bethesda guidelines are useful for selecting patients for microsatellite instability testing. MLH1 and MSH2 testing should be recommended in all patients with colorectal cancer and microsatellite instability who fulfill at least one Bethesda criterion. MLH1 promoter methylation may accompany rather than initiate carcinogenesis in patients with colorectal cancer who have mismatch repair gene defects.