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 11 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 11 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.