2026-04-13T12:34:07Zhttps://recercat.cat/oai/request

oai:recercat.cat:2445/1326612025-11-20T13:50:38Zcom_2072_1057col_2072_478799col_2072_478858col_2072_478916col_2072_478917

00925njm 22002777a 4500 dc Gallardo Gómez, María author Moran, Sebastian author Páez de la Cadena, María author Martínez Zorzano, Vicenta Soledad author Rodríguez Berrocal, Francisco Javier author Rodríguez Girondo, Mar author Esteller, Manel author Cubiella, Joaquín author Bujanda, Luis author Castells Garangou, Antoni author Balaguer Prunés, Francesc author Jover, Rodrigo author De Chiara, Loretta author 2019-05-03T12:48:36Z 2019-05-03T12:48:36Z 2018-04-15 2019-05-03T12:48:36Z BACKGROUND: Colorectal cancer is the fourth cause of cancer-related deaths worldwide, though detection at early stages associates with good prognosis. Thus, there is a clear demand for novel non-invasive tests for the early detection of colorectal cancer and premalignant advanced adenomas, to be used in population-wide screening programs. Aberrant DNA methylation detected in liquid biopsies, such as serum circulating cell-free DNA (cfDNA), is a promising source of non-invasive biomarkers. This study aimed to assess the feasibility of using cfDNA pooled samples to identify potential serum methylation biomarkers for the detection of advanced colorectal neoplasia (colorectal cancer or advanced adenomas) using microarray-based technology. RESULTS: cfDNA was extracted from serum samples from 20 individuals with no colorectal findings, 20 patients with advanced adenomas, and 20 patients with colorectal cancer (stages I and II). Two pooled samples were prepared for each pathological group using equal amounts of cfDNA from 10 individuals, sex-, age-, and recruitment hospital-matched. We measured the methylation levels of 866,836 CpG positions across the genome using the MethylationEPIC array. Pooled serum cfDNA methylation data meets the quality requirements. The proportion of detected CpG in all pools (> 99% with detection p value < 0.01) exceeded Illumina Infinium methylation data quality metrics of the number of sites detected. The differential methylation analysis revealed 1384 CpG sites (5% false discovery rate) with at least 10% difference in the methylation level between no colorectal findings controls and advanced neoplasia, the majority of which were hypomethylated. Unsupervised clustering showed that cfDNA methylation patterns can distinguish advanced neoplasia from healthy controls, as well as separate tumor tissue from healthy mucosa in an independent dataset. We also observed that advanced adenomas and stage I/II colorectal cancer methylation profiles, grouped as advanced neoplasia, are largely homogenous and clustered close together. CONCLUSIONS: This preliminary study shows the viability of microarray-based methylation biomarker discovery using pooled serum cfDNA samples as an alternative approach to tissue specimens. Our strategy sets an open door for deciphering new non-invasive biomarkers not only for colorectal cancer detection, but also for other types of cancers. Càncer colorectal Epigenètica ADN Metilació Marcadors bioquímics Colorectal cancer Epigenetics DNA Methylation Biochemical markers A new approach to epigenome-wide discovery of non-invasive methylation biomarkers for colorectal cancer screening in circulating cell-free DNA using pooled samples