AIM: In colorectal cancer (CRC), improved methods for early detection are essential for increasing survival. Hypermethylated DNA in blood or stool has been proposed as a biomarker for CRC. In recent years, biochemical methods have improved, and several hypermethylated genes that are sensitive and specific for CRC have been proposed. Articles describing the use of hypermethylated promoter regions in blood or stool as biomarkers for CRC were systematically reviewed.
METHOD: The Medline, Web of Science, and Embase databases were used in a systematic literature search. Studies were included if they analysed hypermethylated genes from stool or blood samples in correlation with CRC. Non-English-language studies and studies based on animal models or cell lines were excluded.
RESULTS: The literature search yielded 72 articles, including 43 addressing blood samples and 29 addressing stool samples. In blood samples, hypermethylated P16, HLTF, TMEFF1, ALX4, VIM, and FBN2 were associated with poor prognosis, hypermethylated APC, TAC1, SEPT9, NEUROG1, RASSF1A, SDC2, and THBD were detected in early-stage CRC, and hypermethylated P16 and TFPI2 could detect CRC recurrence. In stool samples, hypermethylated BMP3, PHACTR3, SFRP2, SPG20, TFPI2, and TMEFF2 could detect CRC in the early stages.
CONCLUSION: Hypermethylation of the promoters of specific genes measured in blood or stool samples could be used to detect CRC and could provide prognostic information. The majority of studies include, however, only a few patients with poorly defined control groups. Further studies are therefore needed before hypermethylated DNA can be applied as a clinical biomarker for CRC detection and prognosis. This article is protected by copyright. All rights reserved.