Detection of methylated SEPT9 DNA in peripheral blood for diagnosis of colorectal cancer

BackgroundColorectal cancer (CRC) remains a leading cause of cancer-related death worldwide. Although colonoscopy is effective screening method, its widespread adoption is hampered by poor compliance. Development of patient-friendly screening methods that are minimally invasive is of paramount importance to improve CRC screening participation.MethodsA single-center case-control study was conducted. Blood samples were collected from 119 participants (79 CRC patients, 20 patients with colorectal adenomas, and 20 healthy colonoscopy-negative controls) during May 2023 and March 2025. The methylated SEPT9 (mSEPT9) DNA in peripheral blood was analyzed by droplet digital polymerase chain reaction (ddPCR).ResultsThe sensitivity and specificity of mSEPT9 detection in peripheral blood for diagnosis of all stages of CRC patients was 68.35% and 95.00%, respectively. The positive rate were similar between left-sided CRC and right-sided CRC (65.31% vs 72.41%，p ＞ 0.05). mSEPT9 detection in all healthy people with normal colonoscopy were negative. When mSEPT9 detection was combined with CEA and CA199, positive rate could be raised to 82.67%.ConclusionsBlood-based mSEPT9 detection by ddPCR method is a sensitive and specific method for non-invasive diagnosis of CRC. Combination with CEA and CA19-9 could improve its performance. It may serve as a viable alternative for individuals unwilling or unable to undergo invasive procedures.