Clinical significance of detection of CK-20 mRNA in exfoliated urothelial cells of patients with bladder cancer

Objective To explore the feasibility of detecting the cytokeratin 20 (CK-20) mRNA in exfoliated urothelial cells for the diagnosis of bladder carcinoma. Methods Reverse transcriptase-polymerase chain reaction (RT-PCR) was used to detect the expression of CK-20 mRNA in cells collected from the urine of 45 cases of bladder cancer, 15 cases of cystitis accompanied by hematuria, 10 healthy volunteers, and 7 different cell lines, including bladder cancer cell line T24, kidney cancer 786-0 and GRC-1, breast cancer MCF-7 and MDA-MB-435, and ovary cancer SKOV 3 and 3AO. Results CK-20 mRNA expression was detected in 36 of 41 cases of bladder transitional cell carcinoma (87.80%), in 18 of the 21 GⅠ patients (85.71%), in 11 of the 13 GⅡ patients (84.62%), in 7 of the 7 GⅢ patients (100%), in 20 of the 22 T a-1 patients (90.91%), and in 16 of the 19T 2-4 patients (84.21%). Sensitivity of the method was found to be 87.80%, whereas specificity was 73.33%. In 15 patients with hematuria, there were 4 cases of false positive: 1 case of BPH, 1 case of atypical hyperplasia, 1 case of chronic inflammation, and 1 case undergoing TURP previously. CK-20 amplification band was also obtained in all of 19 cases of bladder transitional cell tumor tissues and bladder cancer cell line T24, but not in 4 patients with non-transitional cell carcinoma and 6 other tumor cell lines. No false positive cases were found in the healthy control group. Conclusion These results suggest that CK-20 might be a useful tumor marker for early noninvasive diagnosis and follow-up of bladder cancer by detecting CK-20 mRNA expression of uroepithelial cells from the voided urine specimen by RT-PCR.