title: DNA methylation as an epigenetic biomarker in colorectal cancer.
abstract: Sporadic colorectal cancer (CRC) is a consequence of the accumulation of genetic and epigenetic alterations that result in the transformation of normal colonic epithelial cells to adenocarcinomas. Studies have indicated that a common event in the tumorigenesis of CRC is the association of global hypomethylation with discrete hypermethylation at the promoter regions of specific genes that are involved in cell cycle regulation, DNA repair, apoptosis, angiogenesis, adhesion and invasion. The present study aimed to investigate the epigenetic changes (DNA methylation) in 24 candidate genes in CRC. A total of 10 candidate hypermethylated (HM) and unmethylated (UM) genes were identified that may be useful epigenetic markers for non-invasive CRC screening. The five genes that had the highest average UM percentages in the control group wereMLH1(71.7%),DKK2(69.6%),CDKN2A(68.4%),APC(67.5%) andhsa-mir-342(67.4%).RUNX3(58.9%),PCDH10(55.5%),SFRP5(52.1%),IGF2(50.4%) andHnf1b(50.0%) were the five genes with the highest average HM percentages in the test group. In summary, the present preliminary study identified the methylation profiles of normal and cancerous colonic epithelial tissues, and provided the groundwork for future large-scale methylation studies.
authors.affiliation: Oncology Group, Gastroenterology Division, Federal University of São Paulo, São Paulo 04023-900, Brazil.
authors.forename: Tiago Donizetti
authors.initials: TD
authors.lastname: Silva
authors.forename: Veronica Marques
authors.initials: VM
authors.lastname: Vidigal
authors.forename: Aledson Vitor
authors.initials: AV
authors.lastname: Felipe
authors.forename: Jacqueline Miranda
authors.initials: JM
authors.lastname: DE Lima
authors.forename: Ricardo Artigiani
authors.initials: RA
authors.lastname: Neto
authors.forename: Sarhan Sidney
authors.initials: SS
authors.lastname: Saad
authors.forename: Nora Manoukian
authors.initials: NM
authors.lastname: Forones
keywords: colorectal cancer; epigenetics; methylation