title: Colorectal cancer DNA methylation patterns from patients in Manaus, Brazil.
abstract: BACKGROUND
  DNA methylation is commonly linked with the silencing of the gene expression for many tumor suppressor genes. As such, determining DNA methylation patterns should aid, in times to come, in the diagnosis and personal treatment for various types of cancers. Here, we analyzed the methylation pattern from five colorectal cancer patients from the Amazon state in Brazil for four tumor suppressor genes, viz.: DAPK, CDH1, CDKN2A, and TIMP2 by employing a polymerase chain reaction (PCR) specific to methylation. Efforts in the study of colorectal cancer are fundamental as it is the third most of highest incidence in the world.
  
  
  RESULTS
  Tumor biopsies were methylated in 1/5 (20%), 2/5 (40%), 4/5 (80%), and 4/5 (80%) for CDH1, CDKN2A, DAPK, and TIMP2 genes, respectively. The margin biopsies were methylated in 3/7 (43%), 2/7 (28%), 7/7 (100%), and 6/7 (86%) for CDH1, CDKN2A, DAPK, and TIMP2, respectively.
  
  
  CONCLUSIONS
  Our findings showed DAPK and TIMP2 to be methylated in most samples from both tumor tissues and adjacent non-neoplastic margins; thus presenting distinct methylation patterns. This emphasizes the importance of better understanding of the relation of these patterns with cancer in the context of different populations.
authors.affiliation: Laboratory of Chromatography and Mass Spectrometry, Institute of Exact Sciences, Federal University of Amazonas, Manaus, Brazil. fabiana_greyce@hotmail.com.
authors.forename: Fabiana Greyce Oliveira
authors.initials: FG
authors.lastname: Almeida
authors.affiliation: Leonidas and Maria Deane Institute, FIOCRUZ, Manaus, Brazil. priscila_aquino23@hotmail.com.
authors.forename: Priscila Ferreira
authors.initials: PF
authors.lastname: de Aquino
authors.affiliation: Laboratory of Chromatography and Mass Spectrometry, Institute of Exact Sciences, Federal University of Amazonas, Manaus, Brazil. souzaadl@hotmail.com.
authors.forename: Afonso Duarte Leão
authors.initials: AD
authors.lastname: de Souza
authors.affiliation: Laboratory of Chromatography and Mass Spectrometry, Institute of Exact Sciences, Federal University of Amazonas, Manaus, Brazil. antoniaqlsouza@yahoo.com.br.
authors.forename: Antonia Queiroz Lima
authors.initials: AQ
authors.lastname: de Souza
authors.affiliation: High School of Health, Amazon State University, Manaus, Brazil. vinhotesonia@gmail.com.
authors.forename: Sonia
authors.initials: S
authors.lastname: do Carmo Vinhote
authors.affiliation: Laboratory of Molecular Pathology, Department of Pathology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. maccormick.thais@gmail.com.
authors.forename: Thaís Messias
authors.initials: TM
authors.lastname: Mac-Cormick
authors.affiliation: Laboratory of Molecular Pathology, Department of Pathology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. marcelosoaresdamota@gmail.com.
authors.forename: Marcelo Soares
authors.initials: MS
authors.lastname: da Mota Silva
authors.affiliation: Department of Abdominal Surgery, Oncology Control Center Foundation of Amazon State, Manaus, Brazil. sidney.chalub@hotmail.com.
authors.forename: Sidney Raimundo Silva
authors.initials: SR
authors.lastname: Chalub
authors.affiliation: Laboratory of Proteomics and Protein Engineering, Carlos Chagas Institute, Curitiba, Brazil. juli_f@yahoo.com.
authors.forename: Juliana
authors.initials: J
authors.lastname: de Saldanha da Gama Fischer
authors.affiliation: Laboratory of Proteomics and Protein Engineering, Carlos Chagas Institute, Curitiba, Brazil. paulo@pcarvalho.com.
authors.forename: Paulo Costa
authors.initials: PC
authors.lastname: Carvalho
authors.affiliation: Laboratory of Molecular Pathology, Department of Pathology, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil. gloria@gcarvalho.org.
authors.forename: Maria
authors.initials: M
authors.lastname: da Gloria da Costa Carvalho
mesh_terms: D000328:Adult; D000368:Aged; D001938:Brazil; D015179:Colorectal Neoplasms / Q000235:genetics*; D019175:DNA Methylation / Q000235:genetics*; D005260:Female; D020868:Gene Silencing; D016147:Genes, Tumor Suppressor; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic