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BackgroundEarly detection through screening programs has proven to be the most effective strategy to reduce the incidence and mortality of colorectal cancer. The most widely implemented non-invasive screening test is the fecal immunochemical test, which presents an inadequate sensitivity for the detection of precancerous advanced adenomas. This fact, together with the modest participation rates in screening programs, highlights the need for a blood test that could improve both the adherence to screening and the selection to colonoscopy.MethodsIn this study, we conducted a serum-based discovery and validation of circulating cell-free DNA (cfDNA) methylation biomarkers for colorectal cancer screening in a multicentre cohort of 433 serum samples including healthy controls, benign pathologies, advanced adenomas, and colorectal cancer. First, we performed an epigenome-wide methylation analysis with the MethylationEPIC array in 280 cfDNA samples using a pooling approach, followed by a robust prioritization of candidate biomarkers for the joint detection of advanced adenomas and colorectal cancer (advanced neoplasia). Then, candidate biomarkers were validated by pyrosequencing in independent individual 153 cfDNA samples.ResultsWe report GALNT9, UPF3A, WARS, and LDB2 as new non-invasive methylation biomarkers for the early detection of colorectal advanced neoplasia. A model composed of GALNT9, UPF3A, WARS, and LDB2 reported a sensitivity of 62.1% and a specificity of 97.4% for the detection of advanced neoplasia. On the other hand, the combination of GALNT9 and UPF3A by logistic regression discriminated advanced neoplasia with 78.8% sensitivity and 100% specificity, outperforming the commonly used fecal immunochemical test and the methylated SEPT9 blood test.ConclusionsSerum methylation levels of GALNT9, UPF3A, WARS, and LDB2 represent highly specific and sensitive novel blood-based biomarkers for the detection of colorectal cancer and premalignant advanced adenomas of both distal and proximal locations. The reported results show the feasibility of DNA sample pooling strategies for biomarker discovery. Overall, this study highlights the utility of cfDNA methylation for the early detection of colorectal neoplasia, with the potential to be implemented as a non-invasive test for colorectal cancer screening. |
