Absence of microsatellite instability in transitional cell carcinoma of the bladder

Objectives. To investigate the prevalence of the microsatellite instability related to mismatch repair (MMR) gene defects using a panel of six microsa tellite markers, as recommended by a recent workshop on microsatellite inst ability in colon cancer, because it is still unclear whether abnormalities in DNA MMR genes are involved in transitional cell carcinoma (TCC) of the b ladder. Methods. Three mononucleotide repeats (BAT26, TGF beta RII, and BAX) were s tudied in 33 TCC samples and in four bladder cancer cell lines. Three dinuc leotide repeats (D2S123, D5S346, and D17S250) were studied in 21 of these 3 3 TCC samples. Results, No alteration was detected either in the 33 TCC samples analyzed o r in the four bladder cancer cell lines (T24, J82, 647V, and 1207) studied. A difference between normal and tumor DNA was observed in only 1 of 21 tum or samples for D17S250. Conclusions. These data indicate that microsatellite instability is very un common in TCC of the bladder, (C) 2000, Elsevier Science Inc.