MLH1 and hereditary nonpolyposis colon cancer: Lynch syndrome, also called hereditary nonpolyposis colorectal cancer (HNPCC), is an autosomal dominantly inherited cancer predisposition syndrome primarily associated with germ-line mutations in the MLH1 (MIM# 120436), MSH2 (MIM# 609309), and MSH6 (MIM# 600678) genes [1].