Uroplakin II as a promising marker for molecular diagnosis of nodal metastases from bladder cancer: comparison with cytokeratin 20.

PURPOSE

Current methods used to determine pathological examination of the lymphatics after radical cystectomy are tedious and costly. We performed a systemic study of uroplakin II (UP II) and cytokeratin 20 (CK 20) expression in pelvic lymph nodes on multiple sides in patients with bladder cancer.

MATERIALS AND METHODS

A total of 82 pelvic lymph node and 19 bladder tumor samples were obtained from 21 patients with bladder cancer by radical cystectomy with pelvic lymphadenectomy for reverse transcriptase-polymerase chain reaction assay.

RESULTS

Of the 19 bladder tumor tissue specimens 19 (100%) and 13 (68.4%) were positive for UP II and CK 20 mRNA expression, respectively. UP II mRNA was detected in 15 of 16 pelvic lymph node samples (93.8%) with pathologically proven metastases, whereas 9 (56.6%) were positive for CK 20 mRNA. The reverse transcriptase-polymerase chain reaction assay for UP II was statistically more sensitive than that for CK 20 in detecting not only primary tumors, but also metastatic pelvic lymph nodes (p = 0.0179 and 0.0373, respectively). Of 66 pelvic lymph node samples without metastasis UP II was detected in 6 (10%), while CK 20 was not. In addition, UP II and CK 20 mRNA could be detected in at least 50 and 500 bladder cancer HT1197 cells, respectively.

CONCLUSIONS

These results indicate that UP II might be a more useful marker than CK 20 for detecting micrometastases of bladder cancer in the pelvic lymph nodes, although a greater number of patients and longer followup are needed to come to a definitive conclusion.