title: Microsatellite Instability of Gastric and Colorectal Cancers as a Predictor of Synchronous Gastric or Colorectal Neoplasms.
abstract: OBJECTIVE
  Microsatellite instability (MSI) plays a crucial role in gastrointestinal carcinogenesis. The aim of this study was to clarify whether MSI is a useful marker for predicting synchronous gastric and colorectal neoplasms.
  
  
  METHODS
  Consecutive patients who underwent both esophagogastroduodenoscopy and colonoscopy before the resection of gastric or colorectal cancers were included. MSI was analyzed using two mononucleotide and three dinucleotide markers.
  
  
  RESULTS
  In total, 434 gastric cancers (372 microsatellite stability [MSS], 21 low incidence of MSI [MSI-L], and 41 high incidence of MSI [MSI-H]) and 162 colorectal cancers (138 MSS, 9 MSI-L, and 15 MSI-H) were included. Patients with MSI gastric cancer had a higher prevalence of synchronous colorectal cancer, colorectal adenoma, and gastric adenoma than those with MSS gastric cancers (4.8% vs 0.5%, p=0.023; 11.3% vs 3.2%, p=0.011; 3.2% vs 1.2%, p=0.00, respectively). The prevalence of synchronous colorectal adenomas was highest in MSI-L gastric cancers (19.0%), compared with MSI-H (7.3%) or MSS (3.2%) gastric cancers (p=0.002). In addition, there were no significant differences in the prevalence rates of synchronous colorectal adenoma among the MSI-H (13.3%), MSI-L (11.1%), and MSS (12.3%) colorectal cancers (p=0.987).
  
  
  CONCLUSIONS
  The presence of MSI in gastric cancer may be a predictor of synchronous gastric and colorectal neoplasms, whereas MSI in colorectal cancer is not a predictor of synchronous colorectal adenoma.
authors.affiliation: Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Young Beak
authors.initials: YB
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Sun-Young
authors.initials: SY
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Jeong Hwan
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: In-Kyung
authors.initials: IK
authors.lastname: Sung
authors.affiliation: Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Hyung Seok
authors.initials: HS
authors.lastname: Park
authors.affiliation: Department of Internal Medicine, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Chan Sup
authors.initials: CS
authors.lastname: Shim
authors.affiliation: Department of Pathology, Konkuk University School of Medicine, Seoul, Korea.
authors.forename: Hye Seung
authors.initials: HS
authors.lastname: Han
mesh_terms: D000236:Adenoma / Q000235:genetics* / Q000601:surgery; D000368:Aged; D003113:Colonoscopy; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000601:surgery; D016145:Endoscopy, Digestive System; D005260:Female; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000235:genetics* / Q000601:surgery; D011237:Predictive Value of Tests; D013274:Stomach Neoplasms / Q000235:genetics* / Q000601:surgery
keywords: Adenoma; Colorectal neoplasms; Microsatellite instability; Stomach neoplasms