Center for Human Genetics and Laboratory Diagnostics, Dr. Klein, Dr. Rost and Colleagues

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Carcinoma of the Urinary Bladder (Uro-FISH) [C67.9]

OMIM number: 109800

Dipl.-Ing. (FH) Tanja Hinrichsen

Scientific Background

With 2-3% of all malignomas, the carcinoma of the urinary bladder is the fifth most common type of cancer in men and the second most common urologic tumor. The average age at diagnosis is 65-70 years; only 5% of all patients are less than 45 years old. Risk factors include smoking, exposition to chemicals, certain forms of chronic urinary bladder infection, schistosomiasis (bilharzia) and abuse of analgesics (phenacetin). Signs and symptoms are hematuria as well as painful or frequent urination.

Approx. 70% of all bladder tumors are limited to the urothelium or the lamina propria when the diagnosis is established; in approx. 30% of all cases the tumor has already infiltrated deeper layers of the bladder. There is a correlation between the grade and the stage of the tumor, i. e. superficial tumors are of a lower grade, invasive tumors of a higher grade. Superficial bladder carcinomas have a high tendency of recurrence (up to 70%); 10-30% exhibit a progressive-invasive course, which requires regular invasive controls (cystoscopy).

Compared to normal urothelial cells, tumor cells frequently exhibit an increased number of copies of all chromosomes as well as deletions in the short arm of chromosome 9, which can be detected using UroVysion-FISH test (chromosome 3, 7 and 17, locus-specific probe chromosome 9p21; Abbott, Wiesbaden). The combined morphologic evaluation of urine cytology and FISH enhances the diagnostic sensitivity. Therefore, the intervals of the cytoscopy during follow-up care may be shortened where appropriate. In recent studies, the sensitivity of the FISH analysis was stated to be approx. 92%, even in the case of a very low histologic grade of the tumor (cytology approx. 60%, mitochondrial DNA, Nuclear Matrix Protein 22). A positive UroVysion test, however, does not confirm the diagnosis of “carcinoma of the bladder”. It rather detects genetically abnormal, transformed cells in the urine, which may progress to urothelial carcinoma.