[Detection of circulating cancer cells by nested reverse transcription-polymerase chain reaction of cytokeratin-19 in patients with renal cell carcinoma].

Detection of circulating cancer cells in peripheral blood may improve cancer staging and monitoring. This study was undertaken to investigate the clinical implications of detection of circulating cancer cells in renal cancer patients. Cytokeratin-19 (CK19) mRNA was amplified by nested reverse transcription-polymerase chain reaction (RT-PCR) in the peripheral blood of 33 healthy volunteers and 19 patients with renal cell carcinoma. The detection limit of the method was 10 cancer cells in 10(7) peripheral blood mononuclear cells. The positive detection rate was 47% for renal cancer patients and 9% for healthy volunteers. The number of patients expressing CK19 mRNA in each clinical stage was 0 out of 3 patients in stage 1; 2 out of 8 (25%) in stage 2; 3 out of 4 (75%) in stage 3; 4 out 4 (100%) in stage 4. A significant correlation was seen between CK19 mRNA expression and clinical stage (p = 0.0023). This method may be useful for early detection of micrometastasis, and facilitate the design of better therapeutic strategies for the treatment of renal cancer patients.