title: High prevalence of deficient mismatch repair phenotype and the V600E BRAF mutation in elderly patients with colorectal cancer.
abstract: OBJECTIVE
  Colorectal cancer (CRC) occurs mostly in the elderly. However, the biology of CRC in elderly has been poorly studied. This study examined the prevalence of deficient mismatch repair phenotype (dMMR) and BRAF mutations according to age.
  
  
  METHODS
  MMR phenotype was prospectively determined by molecular analysis in patients of all ages undergoing surgery for CRC. BRAF V600E mutation status was analysed in a subset of dMMR tumours.
  
  
  RESULTS
  A total of 754 patients who underwent surgery between 2005 and 2008 were included in the study. Amongst them, 272 (36%) were ≥75years old. The proportion of women <75 was 38% and that ≥75 was 53% (p<0.0001). The prevalence of dMMR was 19.4% in patients ≥75 and 10.7% in patients <75 (p=0.0017). For patients ≥75, the prevalence of dMMR was significantly higher in women than in men (27% vs 10.2%, respectively; p=0.003) but was similar in women and men <75 (12.5% vs 9.7%, respectively; p=0.4). We examined BRAF mutation status in 80 patients with dMMR tumours. The V600E BRAF mutation was significantly more frequent in patients ≥75 than in patients <75 (72.2% vs 11.4%, respectively; p<0.001). In patients ≥75, there was no difference in the prevalence of the BRAF V600E mutation according to sex (78% in women and 70% in men, p=0.9).
  
  
  CONCLUSIONS
  The prevalence of dMMR in CRC is high in patients over 75. In elderly patients, dMMR tumours are significantly more frequent in women than in men. The BRAF mutation is frequent in elderly patients with CRC.
authors.affiliation: Gastroenterology, Avicenne Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, University Paris 13, Bobigny, France. Electronic address: thomas.aparicio@avc.aphp.fr.
authors.forename: Thomas
authors.initials: T
authors.lastname: Aparicio
authors.affiliation: Biochemistry, Avicenne Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, University Paris 13, Bobigny, France.
authors.forename: Olivier
authors.initials: O
authors.lastname: Schischmanoff
authors.affiliation: Gastroenterology, Montfermeil Hospital, Montfermeil, France.
authors.forename: Cecile
authors.initials: C
authors.lastname: Poupardin
authors.affiliation: Gastroenterology, Avicenne Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, University Paris 13, Bobigny, France.
authors.forename: Florence
authors.initials: F
authors.lastname: Mary
authors.affiliation: Biochemistry, Bichat Hospital, Sorbonne-Paris Cité, University Paris 7, Paris, France.
authors.forename: Nadem
authors.initials: N
authors.lastname: Soufir
authors.affiliation: Surgery, Jean Verdier Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, University Paris 13, Bondy, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Barrat
authors.affiliation: Gastroenterology, Robert Ballanger Hospital, Aulnay, France.
authors.forename: Guy
authors.initials: G
authors.lastname: Bellaiche
authors.affiliation: Research Unit, Avicenne Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, Université Paris 13, Bobigny, France.
authors.forename: Marouane
authors.initials: M
authors.lastname: Boubaya
authors.affiliation: Anatomopathology, Bichat Hospital, Sorbonne-Paris Cité, University Paris 7, Paris, France.
authors.forename: Laurence
authors.initials: L
authors.lastname: Choudat
authors.affiliation: Anatomopathology, Montfermeil Hospital, Montfermeil, France.
authors.forename: Joel
authors.initials: J
authors.lastname: Cucherousset
authors.affiliation: Oncology, Avicenne Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, University Paris 13, Bobigny, France.
authors.forename: Gaetan
authors.initials: G
authors.lastname: DesGuetz
authors.affiliation: Surgery, Avicenne Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, University Paris 13, Bobigny, France.
authors.forename: Philippe
authors.initials: P
authors.lastname: Wind
authors.affiliation: Gastroenterology, Avicenne Hospital, APHP, HUPSSD, Sorbonne-Paris Cité, University Paris 13, Bobigny, France.
authors.forename: Robert
authors.initials: R
authors.lastname: Benamouzig
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015179:Colorectal Neoplasms / Q000235:genetics*; D053843:DNA Mismatch Repair / Q000235:genetics*; D005260:Female; D015577:Geriatric Assessment / Q000379:methods* / Q000706:statistics & numerical data; D006801:Humans; D008297:Male; D009154:Mutation / Q000235:genetics*; D010641:Phenotype; D015995:Prevalence; D011446:Prospective Studies; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics*; D012737:Sex Factors; D016019:Survival Analysis
chemical_list: D048493:Proto-Oncogene Proteins B-raf
keywords: BRAF; Carcinogenesis; Colorectal cancer; Mismatch repair; The elderly