Short telomeres and chromosome instability prior to histologic malignant progression and cytogenetic aneuploidy in papillary urothelial neoplasms

Purpose Evaluation of the relationships existing among 3 histologic types of urothelial tumors, chromosomal instability, and telomere length. Patients and methods We examined 37 consecutive cases of papillary urothelial neoplasm, from which 26 (70.3%) were suitable for karyotype analysis, comprising 7 papillary urothelial neoplasms of low malignant potential (PUNLMPs), 10 low-grade papillary urothelial carcinomas (PUCs), and 9 high-grade PUCs. We performed karyotype and anaphase bridge analyses, and measured telomere lengths by quantitative fluorescence in situ hybridization. Results PUNLMPs were always diploid and had anaphase bridges. Low-grade PUCs showed diploidy ( n = 2), hypoploidy ( n = 4) and polyploidy ( n = 4), and high-grade PUCs showed diploidy ( n = 1) and polyploidy ( n = 8); both had anaphase bridges. The incidence of anaphase bridges did not differ significantly between PUNLMPs and high-grade PUCs ( P = 0.105). The telomere lengths of PUNLMP, low-grade PUC, and high-grade PUC, expressed as mean telomere fluorescence units (TFU)±SD, were 7906±3197, 4893±1567, and 3299±1406, respectively. The differences among the 3 groups were significant. However, 42.9% of the PUNLMPs had shorter telomeres than the mean value for low-grade PUCs, and 30.0% of the low-grade PUCs had shorter telomeres than those for high-grade PUCs. There was an inverse correlation between telomere length and the incidence of anaphase bridges. Conclusions PUNLMP appears to progress to low-grade PUC and high-grade PUC in association with telomere shortening and chromosomal instability. Our data suggest that critically shortened telomeres cause chromosomal instability during progression of papillary urothelial neoplasms.