Chromosome constitution of transitional cell carcinoma of the urinary bladder

The chromosome constitution of 64 bladder tumors was examined. All well-differentiated, moderately differentiated, and 20% of poorly differentiated tumors were in the diploid range (42–49 chromosomes); the remainder had high ploidy levels without a modal preference. There are no characteristic karyotypic abnormalities specific to transitional cell carcinomas. Evolution of karyotypic change was observed in several recurrent tumors. The stability of well-differentiated and moderately differentiated tumors is discussed.