RFX4-AS1 and hyperplastic polyp: In order to confirm that methylation alterations among different types of tissues are also reflected in the expression level, in situ hybridization for Uc160, Uc283, and Uc346 was performed on representative tissue specimens from non-neoplastic adjacent tissue, hyperplastic polyps, adenomas, carcinomas, infiltrated lymph nodes, and distant metastatic lesions.