The detection of renal carcinoma cells in the peripheral blood with an enhanced reverse transcriptase-polymerase chain reaction assay for MN/CA9

BACKGROUND, Using a reverse transcriptase-polymerase chain reaction (RT-PCR ) assay, the authors previously determined the expression of MN/CA9 mRNA in renal cell carcinoma (RCC) and its absence in benign renal tissue. In the current study, the utility of an enhanced RT-PCR assay in the detection of renal carcinoma cells in the peripheral blood was assessed. METHODS. An enhanced MN/CA9 RT-PCR assay was applied to peripheral blood sa mples from a total of 96 patients. Forty-two patients had renal tumors, inc luding 5 with benign renal lesions, 28 with localized RCC, and 9 with metas tatic RCC. Fifty-four control patients without renal tumors were similarly tested. Pathologic staging for patients with localized cancer was T1N0M0 fo r 5, T2N0M0 for 9, and T3N0M0 for 14 patients. RESULTS. Cells expressing MN/CA9 were detected in 1 of 54 controls (1.8%) a nd in 18 of 37 cancer patients (49%). Thirteen of twenty eight patients (46 %) with localized RCC and 5 of 9 (56%) with metastatic disease tested posit ive with the assay. No patient with a benign renal tumor exhibited MN/CA9 e xpression. AU blood test results for patients with clear cell RCC were note d to be positive. No correlation was noted between MN/CA9 results and age, gender, or tumor grade. The differences in MN/CA9 results according to T cl assification were not statistically significant. CONCLUSIONS. The enhanced RT-PCR assay for MN/CA9 is a highly specific tech nique for detecting circulating renal carcinoma cells in the peripheral blo od, and it may prove useful in the diagnosis and monitoring of RCC. (C) 199 9 American Cancer Society.