The CancerWeb Report, What's New In Cancer: November, 1996
Bladder Cancer

• p53 mutations as biomarkers for bladder cancer - Loss or mutation of the p53 gene occurs in about 50% of bladder cancers. We have discussed this topic under the heading "p53 gene mutations and high-risk bladder cancer" in the Bladder Cancer section of the June, 1996 issue of the CancerWeb Report. In the October, 1996 issue of Clinical Cancer Research there was a description of a study by researchers from the Universities of Leeds and York in the UK on patients with multifocal bladder cancer, that is with disease at multiple sites in the bladder. They examined p53 mutations in bladder cancer in more detail. Overall 46% of tumor samples from 28 patients had p53 mutations, the same percentage as has been found in many other studies. The p53 mutation that was found in each primary tumor also was seen in 16 of 17 episodes of tumor recurrence. Using the PCR technique to amplify the amount of p53 DNA, they found that in 24 of 30 urine samples from 8 patients, the mutations in the cells in the urine sediment were the same as in the primary tumor; the remaining 6 were negative for tumor on cystoscopy. However, in 6 of the samples with mutations the bladder was also found negative for tumor on cystoscopy at the time urines were collected. These results not only support use of a urine test for bladder cancer based on p53 and perhaps other markers, but they also provide valuable information about bladder cancer. They support the idea that in multifocal disease, the cancer starts from a single cell clone which seeds to other areas, rather than originating as separate disease at each site. They also suggest that tumor cell clones that are not detectable may persist for as long as 97 months, the longest follow-up time. (Xu, Clin Cancer Res 2:1795, 1996)