To eliminate potential confounding effect of HNPCC (hereditary nonpolyposis colorectal cancer), we identified 19 possible or suspected HNPCC cases [i.e., MSI-high CIMP-low/0 tumors (none of which turned out to be BRAF-mutated) with any of the followings: (1) positive family history of colorectal cancer in at least one first-degree relative; (2) loss of MLH1 without evidence of MLH1 methylation; (3) loss of PMS2 without evidence of MLH1 loss; (4) loss of MSH2 and/or MSH6]. The gene discussed is PMS2; the disease is hereditary nonpolyposis colon cancer.