Clinical sensitivity of p53 mutation detection in matched bladder tumor, bladder wash, and voided urine specimens

Mutations in the p53 tumor suppressor gene may correlate with an increased risk of recurrence and disease progression in patients with bladder carcinoma. The ability to accurately and sensitively detect p53 mutations in cytology specimens may be of benefit in the treatment of bladder carcinoma patients with superficial, minimally invasive disease.

Genomic DNA was isolated from 49 cases, each of which was comprised of matched bladder tumor tissue, bladder wash, and voided urine specimens obtained concurrently at a single institution. The genomic DNA was analyzed for mutations in the p53 tumor suppressor gene using a p53 mutation detection assay. Automated dideoxy sequencing of mutant specimens also was performed.

Of the 49 cases, 29 (59%) showed no evidence of p53 mutations in the tumor, bladder wash, or voided urine specimens. Of the remaining 20 cases, 19 showed evidence of mutations in the tumor. Of these 19 p53 mutant bladder tumors, 16 (84%) were detected in the matched bladder wash and 16 (84%) were detected in the matched voided urine specimens. One case resulted in the detection of mutant p53 in the voided urine and the bladder wash, but not in the tumor. Analysis of the results between tumor tissue and bladder wash or tumor and voided urine showed 84.2% sensitivity, 96.8% specificity, and 91.8% accuracy. Sequence analysis of the mutant cases showed that the mutations detected in the tumor tissue were the same mutations detected in the bladder wash and the voided urine specimens.

Both voided urine and bladder wash specimens from patients with bladder carcinoma were found to provide a high rate of clinical accuracy for the determination of the p53 gene status in patients with bladder tumors.