Analysis of LINE-1 DNA Methylation in Colorectal Cancer, Precancerous Lesions, and Adjacent Normal Mucosa.

: Colorectal cancer (CRC) is a major cause of cancer morbidity and mortality worldwide. Genetic and epigenetic changes, especially DNA methylation alterations, are key in CRC development. hypomethylation marks global DNA methylation loss and genomic instability, making it a potential early CRC biomarker. This study investigates the methylation status of in colorectal adenocarcinoma, precancerous lesions (tubular and serrated adenomas), and the surrounding normal mucosa, aiming to elucidate its role as an epigenetic marker in early colorectal tumorigenesis. : Paired lesion and normal tissue samples from 66 patients were analyzed for LINE-1 methylation at three CpG sites using bisulfite pyrosequencing. Adenocarcinomas and tubular adenomas showed significant hypomethylation, especially at loci A and B, while serrated adenomas exhibited no significant differences. : hypomethylation is associated with colorectal tumorigenesis, with distinct patterns observed between tubular and serrated adenomas, indicating distinct pathways forming and progressing specific adenomas. These findings support the potential of methylation as an early epigenetic biomarker for CRC risk stratification and highlight the need for further research into its clinical utility.