Study of Allelic Losses on 3p, 6q, and 17p in Human Urothelial Cancer

Forty-eight transitional cell carcinomas of the bladder and three transitional cell carcinomas of the renal pelvis were examined for loss of heterozygosity (LOH) on chromosomes 3p, 6q, and 17p. The most frequent allelic loss was seen on 17p (18/36, 50%) followed by 6q (6/22, 27%), and 3p (5/22, 23%). In cases with LOH at more than one locus, the same DNA sample often varied in degree of signal reduction for missing alleles. This observation indicates that LOH studies can serve to detect intratumor heterogeneity. No correlation was found between allelic losses at these chromosome arms and tumor grade and stage. Allelic losses on 6q were associated with tumors having a solid growth pattern; in this kind of tumors, allelic losses on 3p were associated with invasion.