title: Microbial mucosal colonic shifts associated with the development of colorectal cancer reveal the presence of different bacterial and archaeal biomarkers.
abstract: BACKGROUND
  Epidemiological studies demonstrate a link between gastrointestinal cancers and environmental factors such as diet. It has been suggested that environmental cancer risk is determined by the interaction between diet and microbes. Thus, the purpose of this study was to examine the hypothesis that microbiota composition during colorectal cancer (CRC) progression might differ depending on the stage of the disease.
  
  
  METHODS
  A total of 28 age-matched and sex-matched subjects, seven with CRC adenocarcinoma, 11 with tubular adenomas and ten healthy subjects with intact colon, were included into the study. Microbiomes from mucosal and fecal samples were analyzed with 16S ribosomal RNA gene pyrosequencing, together with quantitative PCR of specific bacteria and archaea.
  
  
  RESULTS
  The principal coordinates analysis clearly separated healthy tissue samples from polyps and tumors, supporting the presence of specific bacterial consortia that are associated with affected sites and that can serve as potential biomarkers of CRC progression. A higher presence of Fusobacterium nucleatum and Enterobacteriaceae was found by qPCR in samples from CRC compared to healthy controls. We observed a correlation between CRC process development and levels of Methanobacteriales (R = 0.537, P = 0.007) and Methanobrevibacterium (R = 0.574, P = 0.03) in fecal samples.
  
  
  CONCLUSIONS
  Differences in microbial and archaeal composition between mucosal samples from healthy and disease tissues were observed in tubular adenoma and adenocarcinoma. In addition, microbiota from mucosal samples represented the underlying dysbiosis, whereas fecal samples seem not to be appropriate to detect shifts in microbial composition. CRC risk is influenced by microbial composition, showing differences according to disease progression step and tumor severity.
authors.affiliation: Department of Biotechnology, Institute of Agrochemistry and Food Technology, Spanish National Research Council (IATA-CSIC), Av. Agustin Escardino 7, 49860, Paterna, Valencia, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Mira-Pascual
authors.forename: R
authors.initials: R
authors.lastname: Cabrera-Rubio
authors.forename: S
authors.initials: S
authors.lastname: Ocon
authors.forename: P
authors.initials: P
authors.lastname: Costales
authors.forename: A
authors.initials: A
authors.lastname: Parra
authors.forename: A
authors.initials: A
authors.lastname: Suarez
authors.forename: F
authors.initials: F
authors.lastname: Moris
authors.forename: L
authors.initials: L
authors.lastname: Rodrigo
authors.forename: A
authors.initials: A
authors.lastname: Mira
authors.forename: M C
authors.initials: MC
authors.lastname: Collado
mesh_terms: D000230:Adenocarcinoma / Q000382:microbiology*; D000236:Adenoma / Q000382:microbiology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001105:Archaea / Q000302:isolation & purification*; D001419:Bacteria / Q000302:isolation & purification*; D016022:Case-Control Studies; D003106:Colon / Q000382:microbiology; D015179:Colorectal Neoplasms / Q000382:microbiology*; D018450:Disease Progression; D005243:Feces / Q000382:microbiology; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000382:microbiology*; D008297:Male; D064307:Microbiota; D008875:Middle Aged; D012336:RNA, Ribosomal, 16S / Q000235:genetics
chemical_list: D012336:RNA, Ribosomal, 16S