title: Lower prevalence of Lynch syndrome in colorectal cancer patients in a Japanese hospital-based population.
abstract: OBJECTIVE
  The aim of this study was to investigate the prevalence of Lynch syndrome among Japanese patients with surgically resected colorectal cancer at a single institution.
  
  
  METHODS
  Of 616 colorectal cancer patients who underwent surgical operation in our institution from January 2005 to August 2010, immunohistochemistry analyses for mismatch repair proteins (MLH1, MSH2, MSH6, and PMS2) and microsatellite instability (MSI) testing for surgically resected, formalin-fixed paraffin-embedded colorectal cancer specimens from 138 colorectal cancer patients under 60 years of age were undertaken. Hypermethylation of the MLH1 promoter and BRAF mutation were analyzed where necessary.
  
  
  RESULTS
  Seven patients were identified as candidates for genetic testing by mismatch repair protein loss (n = 7) or MSI-H (n = 6). Methylation of MLH1 was detected in one case. Three patients were diagnosed with Lynch syndrome, comprising 2.2 % of the total colorectal cancer patients younger than 60 years of age.
  
  
  CONCLUSIONS
  The prevalence of Lynch syndrome among hospital-based diagnosed cancer patients may therefore be lower than expected in Japan compared with Western populations.
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan. kumamotk@fmu.ac.jp.|Department of Organ Regulatory Surgery, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan. kumamotk@fmu.ac.jp.
authors.forename: Kensuke
authors.initials: K
authors.lastname: Kumamoto
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Ishida
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Okihide
authors.initials: O
authors.lastname: Suzuki
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Tajima
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Noriyasu
authors.initials: N
authors.lastname: Chika
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Koki
authors.initials: K
authors.lastname: Kuwabara
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Keiichiro
authors.initials: K
authors.lastname: Ishibashi
authors.affiliation: Department of Organ Regulatory Surgery, Fukushima Medical University, 1 Hikarigaoka, Fukushima, 960-1295, Japan.
authors.forename: Katsuharu
authors.initials: K
authors.lastname: Saito
authors.affiliation: Department of Pathology, Saitama International Medical Center, Saitama Medical University, Saitama, 350-1298, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Nagata
authors.affiliation: Division of Translational Research, Research Center for Genomic Medicine, Saitama Medical University, Saitama, 350-1241, Japan.
authors.forename: Hidetaka
authors.initials: H
authors.lastname: Eguchi
authors.affiliation: Department of Pathology, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Junichi
authors.initials: J
authors.lastname: Tamaru
authors.affiliation: Department of Digestive Tract and General Surgery, Saitama Medical Center, Saitama Medical University, Saitama, 350-8550, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Iwama
mesh_terms: D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000032:analysis; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics* / Q000601:surgery; D019175:DNA Methylation; D053843:DNA Mismatch Repair / Q000235:genetics; D005260:Female; D005820:Genetic Testing; D006761:Hospitals / Q000706:statistics & numerical data*; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D000070957:MutL Protein Homolog 1 / Q000032:analysis / Q000235:genetics; D009154:Mutation; D015995:Prevalence; D011401:Promoter Regions, Genetic; D048493:Proto-Oncogene Proteins B-raf / Q000235:genetics
chemical_list: D015415:Biomarkers; C501486:MLH1 protein, human; C482119:BRAF protein, human; D048493:Proto-Oncogene Proteins B-raf; D000070957:MutL Protein Homolog 1
keywords: Colorectal cancer; Lynch syndrome; Mismatch repair gene