title: High-risk and low-risk gastric cancer areas in Italy and its association with microsatellite instability.
abstract: OBJECTIVE
  The different pathological characteristics and prognoses between gastric cancer patients coming from high-risk (group A) and low-risk (group B) areas of Italy were analyzed. We investigated a suspected difference in microsatellite instability (MSI) between these two groups.
  
  
  METHODS
  MSI analyses of 452 gastric cancer patients were performed using five quasimonomorphic mononucleotide repeats NR-21, NR-24, NR-27, BAT-25, and BAT-26. MSI analysis was done by PCR usage. An allelic profile of these five mononucleotides was detected on an automated DNA sequencer ABI PRISM 3100 Genetic Analyser. Data were analyzed according to high-risk and low-risk gastric cancer areas.
  
  
  RESULTS
  MSI was observed in 23.9 % of all gastric cancer patients studied. Patients from group A showed a higher rate of MSI (28.4 %) than from group B (13.5 %) (p < 0.001). We analyzed this association together with tumor location and Lauren classification: A nonsignificant differences were seen when analyzing cardia and non-cardia tumors (p = 0.854) but significant for Lauren histotype (p = 0.028). There was no statistical difference in survival between high-risk and low-risk areas (p = 0.437), with a nonsignificant trend for better survival in the high-risk group, especially when measured over a longer period of time. Analyzing MSI or MSS in these groups, the survival curves were almost the same.
  
  
  CONCLUSIONS
  A higher frequency of MSI in patients coming from high-risk areas may help explain geographical differences in gastric cancer. The trend of better survival in high-risk areas may be due to a higher rate of MSI gastric cancer patients.
authors.affiliation: General Surgery and Surgical Oncology Department, University of Siena, viale Bracci 16, 53-100, Siena, Italy. polom.karol@gmail.com.
authors.forename: Karol
authors.initials: K
authors.lastname: Polom
authors.affiliation: General Surgery and Surgical Oncology Department, University of Siena, viale Bracci 16, 53-100, Siena, Italy.
authors.forename: Daniele
authors.initials: D
authors.lastname: Marrelli
authors.affiliation: General Surgery and Surgical Oncology Department, University of Siena, viale Bracci 16, 53-100, Siena, Italy.
authors.forename: Valeria
authors.initials: V
authors.lastname: Pascale
authors.affiliation: Section of Pharmacology and University Center DIFF-Drug Innovation Forward Future, Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
authors.forename: Giandomenico
authors.initials: G
authors.lastname: Roviello
authors.affiliation: General Surgery and Surgical Oncology Department, University of Siena, viale Bracci 16, 53-100, Siena, Italy.
authors.forename: Costantino
authors.initials: C
authors.lastname: Voglino
authors.affiliation: University of Medical Sciences, Poznan, Poland.
authors.forename: Henry
authors.initials: H
authors.lastname: Rho
authors.affiliation: Department of Pathology, Azienda Ospedaliera Universitaria Senese, Siena, Italy.
authors.forename: Carla
authors.initials: C
authors.lastname: Vindigni
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Unit of Endoscopy and Gastroenterology, University of Siena, Siena, Italy.
authors.forename: Mario
authors.initials: M
authors.lastname: Marini
authors.affiliation: Department of Medicine, Surgery and Neurosciences, Unit of Endoscopy and Gastroenterology, University of Siena, Siena, Italy.
authors.forename: Raffaele
authors.initials: R
authors.lastname: Macchiarelli
authors.affiliation: General Surgery and Surgical Oncology Department, University of Siena, viale Bracci 16, 53-100, Siena, Italy.
authors.forename: Franco
authors.initials: F
authors.lastname: Roviello
mesh_terms: D000368:Aged; D005260:Female; D020022:Genetic Predisposition to Disease; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D053842:Microsatellite Instability; D013274:Stomach Neoplasms / Q000453:epidemiology / Q000235:genetics*
keywords: Cancer risk; Gastric cancer; Microsatellite instability; Molecular