2.2 methylation-specific PCR detection

All stool samples were handled in a blinded fashion during storage and processing. DNA extraction and qMSP analysis were performed. Patient samples were collected and processed according to the method previously published by our group ^9-11. Briefly, the collection was as follows: collect, one-time, a full stool sample (25-100g), collects intestinal mucosa with an automatic intestinal mucosal collector ⁹, and then extract intestinal mucosal DNA, and transform the DNA with sulfite. Perform fluorescent PCR detection and read the results to calculate the Ct value.