Allelic loss of chromosome 17p in urothelial cancer: strong association with invasive phenotype.

Allelic loss of chromosome 17p with a mutated p53 gene on the remaining allele has been observed in various kinds of human cancers. To examine the significance of allelic loss of chromosome 17p in human urothelial cancer with special attention to the clinicopathological features, 49 tumors with various stages and grades from 43 cases (35 bladder cancers and 8 renal pelvic or ureteral cancers) were examined for loss of heterozygosity using 5 polymorphic probes on chromosome 17p. Thirty-seven cases were informative, and allelic loss of chromosome 17p was observed in 15 (41%) of them. In bladder cancers, the loss of 17p was observed with significantly higher frequency (p < 0.01) in cases with invasive (> or = pT2) tumors (7/10, 70%) than in cases with superficial (pTa or pT1) tumors (4/21, 19%). In renal pelvic or ureteral cancers, none of 2 superficial tumors and all of 4 invasive tumors showed the allelic loss. As to tumor grade, the allelic loss was observed in 1/9 (11%) for grade 1 cases, 6/18 (33%) for grade 2 cases, and 8/10 (80%) grade 3 cases (grade 1 versus 3, p < 0.01; grade 2 versus 3, p < 0.05). On the other hand, examination of clinical features, such as primary tumor site, tumor multiplicity or previous history of urothelial cancer did not significantly influence the frequency of the allelic loss. Our results suggest that the allelic loss of chromosome 17p is strongly associated with invasive phenotype in urothelial cancer. The results further indicate that the 17p deletion may represent a new genetic marker of malignant potentials in urothelial cancers.