title: Aberrant gene promoter methylation associated with sporadic multiple colorectal cancer.
abstract: BACKGROUND
  Colorectal cancer (CRC) multiplicity has been mainly related to polyposis and non-polyposis hereditary syndromes. In sporadic CRC, aberrant gene promoter methylation has been shown to play a key role in carcinogenesis, although little is known about its involvement in multiplicity. To assess the effect of methylation in tumor multiplicity in sporadic CRC, hypermethylation of key tumor suppressor genes was evaluated in patients with both multiple and solitary tumors, as a proof-of-concept of an underlying epigenetic defect.
  
  
  RESULTS
  We examined a total of 47 synchronous/metachronous primary CRC from 41 patients, and 41 gender, age (5-year intervals) and tumor location-paired patients with solitary tumors. Exclusion criteria were polyposis syndromes, Lynch syndrome and inflammatory bowel disease. DNA methylation at the promoter region of the MGMT, CDKN2A, SFRP1, TMEFF2, HS3ST2 (3OST2), RASSF1A and GATA4 genes was evaluated by quantitative methylation specific PCR in both tumor and corresponding normal appearing colorectal mucosa samples. Overall, patients with multiple lesions exhibited a higher degree of methylation in tumor samples than those with solitary tumors regarding all evaluated genes. After adjusting for age and gender, binomial logistic regression analysis identified methylation of MGMT2 (OR, 1.48; 95% CI, 1.10 to 1.97; p = 0.008) and RASSF1A (OR, 2.04; 95% CI, 1.01 to 4.13; p = 0.047) as variables independently associated with tumor multiplicity, being the risk related to methylation of any of these two genes 4.57 (95% CI, 1.53 to 13.61; p = 0.006). Moreover, in six patients in whom both tumors were available, we found a correlation in the methylation levels of MGMT2 (r = 0.64, p = 0.17), SFRP1 (r = 0.83, 0.06), HPP1 (r = 0.64, p = 0.17), 3OST2 (r = 0.83, p = 0.06) and GATA4 (r = 0.6, p = 0.24). Methylation in normal appearing colorectal mucosa from patients with multiple and solitary CRC showed no relevant difference in any evaluated gene.
  
  
  CONCLUSIONS
  These results provide a proof-of-concept that gene promoter methylation is associated with tumor multiplicity. This underlying epigenetic defect may have noteworthy implications in the prevention of patients with sporadic CRC.
authors.affiliation: Department of Gastroenterology, Hospital Clínic, Centro de Investigación Biomédica en Red en el Area temática de Enfermedades Hepáticas y Digestivas, Institut d'investigacions Biomèdiques August Pi i Sunyer, University of Barcelona, Barcelona, Catalonia, Spain.
authors.forename: Victoria
authors.initials: V
authors.lastname: Gonzalo
authors.forename: Juan José
authors.initials: JJ
authors.lastname: Lozano
authors.forename: Jenifer
authors.initials: J
authors.lastname: Muñoz
authors.forename: Francesc
authors.initials: F
authors.lastname: Balaguer
authors.forename: Maria
authors.initials: M
authors.lastname: Pellisé
authors.forename: Cristina
authors.initials: C
authors.lastname: Rodríguez de Miguel
authors.forename: Montserrat
authors.initials: M
authors.lastname: Andreu
authors.forename: Rodrigo
authors.initials: R
authors.lastname: Jover
authors.forename: Xavier
authors.initials: X
authors.lastname: Llor
authors.forename: M Dolores
authors.initials: MD
authors.lastname: Giráldez
authors.forename: Teresa
authors.initials: T
authors.lastname: Ocaña
authors.forename: Anna
authors.initials: A
authors.lastname: Serradesanferm
authors.forename: Virginia
authors.initials: V
authors.lastname: Alonso-Espinaco
authors.forename: Mireya
authors.initials: M
authors.lastname: Jimeno
authors.forename: Miriam
authors.initials: M
authors.lastname: Cuatrecasas
authors.forename: Oriol
authors.initials: O
authors.lastname: Sendino
authors.forename: Sergi
authors.initials: S
authors.lastname: Castellví-Bel
authors.forename: Antoni
authors.initials: A
authors.lastname: Castells
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics*; D019175:DNA Methylation; D044127:Epigenesis, Genetic; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011401:Promoter Regions, Genetic; D012044:Regression Analysis