Infrequent microsatellite instability in urothelial cell carcinoma of the bladder in young patients.
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.
Mongiat-Artus
Pierre
P
Department of Urology, Saint-Louis Hospital and University Paris VII, Paris, France.
Miquel
Catherine
C
van der Aa
Madelon
M
Buhard
Olivier
O
Hamelin
Richard
R
Bangma
Chris
C
Teillac
Pierre
P
van der Kwast
Theodorus
T
Praz
Françoise
F
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