Urinary cytokeratin 20 as a marker for transitional cell carcinoma

Objectives: To determine if detection of cytokeratin 20 (CK20) gene express ion, by reverse transcriptase-polymerase chain reaction (RT-PCR) in urine f rom transitional cell carcinoma (TCC) patients, can provide a new noninvasi ve tool for the follow-up of patients with urothelial carcinoma of the blad der. Methods: Urine was collected from 95 patients previously diagnosed as TCC d uring their follow-up, and from 27 healthy volunteers. All patients had a t ransurethal resection of tumor or biopsies obtained from 'suspicious' areas in the bladder. RNA was extracted from cells collected from the urine and RT-PCR was performed with specific primers for the amplification of cytoker atin 8, a general marker for epithelial cells, and of CK 20, a marker for T CC urothelium. Results: CK20 expression was detected in 86.7% of TCC patients, and only in 3.3% of healthy volunteers (specificity 96.7%). Strong correlation was fou nd between tumor grade and expression of CK20 in urine. All grade III and I V tumors demonstrated positive CK20 expression (100% sensitivity), whereas the sensitivity for lower grades was between 71 and 80%. Among 11 patients with a previous biopsy-proven diagnosis of TCC and a current negative biops y, in 9 patients CK20 expression was detected. Further follow-up of these p atients for a period of 6 months revealed recurrence of TCC in 4 patients. Conclusion: CK20 detection in urine cells is a simple, noninvasive method w ith a high potential to become the marker of choice for monitoring and foll ow-up of TCC patients. More information is needed regarding CK20 expression in nonmalignant urological disease, to evaluate its use for routine screen ing purposes. Copyright (C) 2000 S. Karger AG. Basel.