Microsatellite alterations at chromosomes 9p, 13q, and 17p in nonmuscle-invasive transitional cell carcinomas of the urinary bladder

The clinical behavior of bladder cancer is difficult to predict and prognos tic markers applicable to routinely processed tumor specimens clearly are n eeded. We screened 40 primary Ta and Tl bladder cancers for microsatellite alterations at 9p, 13q, and 17p with PCR, using nine polymorphic microsatel lite markers. DNA was prepared after microdissection of paraffin-embedded t ransurethral resection specimens. PCR products were separated on sequencing gels, and allelic loss as well as band shifts was assessed by comparing al leles of control and tumor tissue. The results were correlated with grade, stage, and clinically documented tumor recurrence. Overall, allelic loss at 9p, 13q, and 17p was present in 35.1%, 25%, and 27.5% of cases, respective ly. Whereas the frequency of allelic loss at 9p was nearly equally distribu ted throughout all tumor grades and stages, the occurrence of allelic loss at 13q and 17p correlated statistically significantly with higher grades an d stage. Band shifts were observed in three cases. Of the 40 patients, 16 h ad tumor recurrence during a follow-up period of 3-49 months (median, 23 mo nths). Kaplan-Meier analysis did not show any statistically significant cor relation between allelic loss at either locus and tumor recurrence. The res ults confirm the role of alterations at 13q and 17p in the progression of b ladder cancer. Allelic loss at 9p seems to be an early event in tumor devel opment. However, the detection of alterations at the three chromosomal loci studied did not have any prognostic value regarding tumor recurrence in th is group of patients.