title: Multiple sporadic colorectal cancers display a unique methylation phenotype.
abstract: Epigenetics are thought to play a major role in the carcinogenesis of multiple sporadic colorectal cancers (CRC). Previous studies have suggested concordant DNA hypermethylation between tumor pairs. However, only a few methylation markers have been analyzed. This study was aimed at describing the epigenetic signature of multiple CRC using a genome-scale DNA methylation profiling. We analyzed 12 patients with synchronous CRC and 29 age-, sex-, and tumor location-paired patients with solitary tumors from the EPICOLON II cohort. DNA methylation profiling was performed using the Illumina Infinium HM27 DNA methylation assay. The most significant results were validated by Methylight. Tumors samples were also analyzed for the CpG Island Methylator Phenotype (CIMP); KRAS and BRAF mutations and mismatch repair deficiency status. Functional annotation clustering was performed. We identified 102 CpG sites that showed significant DNA hypermethylation in multiple tumors with respect to the solitary counterparts (difference in β value ≥0.1). Methylight assays validated the results for 4 selected genes (p = 0.0002). Eight out of 12(66.6%) multiple tumors were classified as CIMP-high, as compared to 5 out of 29(17.2%) solitary tumors (p = 0.004). Interestingly, 76 out of the 102 (74.5%) hypermethylated CpG sites found in multiple tumors were also seen in CIMP-high tumors. Functional analysis of hypermethylated genes found in multiple tumors showed enrichment of genes involved in different tumorigenic functions. In conclusion, multiple CRC are associated with a distinct methylation phenotype, with a close association between tumor multiplicity and CIMP-high. Our results may be important to unravel the underlying mechanism of tumor multiplicity.
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Gonzalo
authors.affiliation: Bioinformatics Unit, CIBERehd, Barcelona, Catalonia, Spain.
authors.forename: Juan Jose
authors.initials: JJ
authors.lastname: Lozano
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Virginia
authors.initials: V
authors.lastname: Alonso-Espinaco
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Leticia
authors.initials: L
authors.lastname: Moreira
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Jenifer
authors.initials: J
authors.lastname: Muñoz
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Maria
authors.initials: M
authors.lastname: Pellisé
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Sergi
authors.initials: S
authors.lastname: Castellví-Bel
authors.affiliation: Department of Gastroenterology, Hospital del Mar, Barcelona, Catalonia, Spain.
authors.forename: Xavier
authors.initials: X
authors.lastname: Bessa
authors.affiliation: Department of Gastroenterology, Hospital del Mar, Barcelona, Catalonia, Spain.
authors.forename: Montserrat
authors.initials: M
authors.lastname: Andreu
authors.affiliation: Department of Medicine and Cancer Center, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Rosa M
authors.initials: RM
authors.lastname: Xicola
authors.affiliation: Department of Medicine and Cancer Center, University of Illinois at Chicago, Chicago, Illinois, United States of America.
authors.forename: Xavier
authors.initials: X
authors.lastname: Llor
authors.affiliation: Galician Public Foundation of Genomic Medicine (FPGMX), CIBERER, Genomics Medicine Group, Hospital Clinico, Santiago de Compostela, University of Compostela, Galicia, Spain.
authors.forename: Clara
authors.initials: C
authors.lastname: Ruiz-Ponte
authors.affiliation: Galician Public Foundation of Genomic Medicine (FPGMX), CIBERER, Genomics Medicine Group, Hospital Clinico, Santiago de Compostela, University of Compostela, Galicia, Spain.
authors.forename: Angel
authors.initials: A
authors.lastname: Carracedo
authors.affiliation: Gastroenterology Unit, Hospital General Universitario, Alicante, Spain.
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Jover
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Antoni
authors.initials: A
authors.lastname: Castells
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red de Enfermedades Hepáticas y Digestivas (CIBERehd), Institut d'Investigacions Biomediques August Pi i Sunyer (IDIBAPS), University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Francesc
authors.initials: F
authors.lastname: Balaguer
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018899:CpG Islands; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D055106:Genome-Wide Association Study; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D011518:Proto-Oncogene Proteins / Q000235:genetics; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins / Q000235:genetics
chemical_list: C117307:KRAS protein, human; D011518:Proto-Oncogene Proteins; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D016283:Proto-Oncogene Proteins p21(ras); D018631:ras Proteins