Glad to know that you are getting FISH. As Allan said, FISH' reliability is that great, but FISH and Immusys are the only FDA-approved urine tests for bladder cancers to be used adjuvant to cystoscopy mainly to check the recurrence of bladder cancer. Cytology and FISH methods of finding cancerous cells in urine are totally different. Cytology depends upon the experience of a pathologist looking through a microscope and FISH checks the abnormalities of chromosomes 3,7,17 and also checks if a specific gene is missing from chromosome 9. As we know, each cell has 23 pairs of chromosomes, each has a DNA. Cancer cells have several mutations in the DNA. Chromosomes 3,7,17 were known to have genes that cause bladder cancer. In the case of chromosome 9, it is known that a certain part of the DNA is missing, there is a high frequency of cancers, including bladder cancer. Chromosome 17 includes the famous p53 tumor suppressor gene. The loss of its function because of mutations and the loss of the p53 gene have been found in almost 50% of muscle-invasive bladder cancer and also in a high percentage of HG non-muscle-invasive bladder cancer. The drawbacks of FISH is more expensive, it is likely that the urine sample needs to be sent to some lab that does FISH often. Also, the technology is old. In 2001, the cost of analyzing a human genome (entire DNA analysis of one person) cost near $100M. So, there was limited information about the relationship between gene mutations and bladder cancer. FISH was developed in that limited environment. Now, it costs less than $1,000 and getting cheaper. So, many researchers are doing genome analysis for bladder cancer and new urine tests are being developed by various companies. Among them, CxBladder has shown to be very promising. Their website says it is now covered by Medicare. The next time you meet with your pathologist, please check with him about new urine tests and let us know. FYI, there are now over 350 genes that have been identified relating to bladder cancer.
www.cxbladder.com/us/