title: Infrequent microsatellite instability in urothelial cell carcinoma of the bladder in young patients.
abstract: OBJECTIVE
  Defects in the DNA mismatch repair result in microsatellite instability (MSI), which characterise most tumours related to the hereditary non-polyposis colorectal cancer syndrome and some sporadic tumours. Several studies have reported the occurrence of MSI in urothelial cell carcinoma (UCC) of the bladder with a particularly high incidence in tumours from young patients. In this study, we have evaluated the occurrence of MSI in primary bladder UCC arising in seventeen young patients selected for being below 45 years of age at diagnosis.
  
  
  METHODS
  Microsatellite analysis has been performed using the panel of five quasimonomorphic mononucleotide repeats (BAT-25, BAT-26, NR-21, NR-24, NR-27) recently recommended to detect MSI tumours. The original Bethesda panel including BAT-25, BAT-26 and three dinucleotide repeats (D2S123, D5S346, D17S250) has further been studied in 10 UCC samples.
  
  
  RESULTS
  MSI has been observed in only one of the 17 bladder UCC studied. Using the original Bethesda panel, identical results were obtained, indicating that the panel of five mononucleotide markers adequately detected MSI in UCC tumours.
  
  
  CONCLUSIONS
  Our data indicate that classical MSI affecting mono- or di-nucleotides are rarely involved in bladder UCC developing in young patients. Further studies using gold standard criteria would help clarifying the involvement of MSI in the pathogenesis of bladder UCC.
authors.affiliation: Department of Urology, Saint-Louis Hospital and University Paris VII, Paris, France.
authors.forename: Pierre
authors.initials: P
authors.lastname: Mongiat-Artus
authors.forename: Catherine
authors.initials: C
authors.lastname: Miquel
authors.forename: Madelon
authors.initials: M
authors.lastname: van der Aa
authors.forename: Olivier
authors.initials: O
authors.lastname: Buhard
authors.forename: Richard
authors.initials: R
authors.lastname: Hamelin
authors.forename: Chris
authors.initials: C
authors.lastname: Bangma
authors.forename: Pierre
authors.initials: P
authors.lastname: Teillac
authors.forename: Theodorus
authors.initials: T
authors.lastname: van der Kwast
authors.forename: Françoise
authors.initials: F
authors.lastname: Praz
mesh_terms: D000328:Adult; D002295:Carcinoma, Transitional Cell / Q000235:genetics* / Q000473:pathology; D053843:DNA Mismatch Repair; D005260:Female; D006801:Humans; D008297:Male; D053842:Microsatellite Instability; D008875:Middle Aged; D009367:Neoplasm Staging; D001749:Urinary Bladder Neoplasms / Q000235:genetics* / Q000473:pathology