Blood-based RT-PCR assays of MN/CA9 or PSMA: Clinical application in renalcancer patients

Objectives. To report a survey of blood-based RNAs obtained from common gro ups of control and renal cancer patients for expression of both MN/CA9 and prostate-specific membrane antigen (PSMA) messenger RNAs. Methods. Reverse transcription polymerase chain reaction (RT-PCR) assays fo r MN/CA9 and PSMA were performed on RNAs extracted from 81 blood samples (5 9 patients with renal cancer, 7 with benign tumors, and 15 control voluntee rs). The results of these assays were statistically analyzed to determine w hether a positive result (individually or combined) correlates with any tum or characteristics. Results. Neither MN/CA9 nor PSMA amplification products were detected in th e RNAs from peripheral blood samples of the 15 control volunteers and from the 7 patients with benign renal tumor (sensitivity 100%). MN/CA9 alone was detected in 11 (19%) of 59 samples and PSMA alone in 12 (20%) of 59 sample s from patients with renal cancer. PSMA positivity was significantly correl ated with vascular invasion of the primary tumor. Expression of one or both of these molecular tumor markers was detected in 21 (36%) of 59 renal canc er patients. When combined, the results of the MN/CA9 and PSMA RT-PCR tests were found to be highly associated with vascular invasion in nephrectomy s pecimens (sensitivity 67%, specificity 77%, odds ratio = 6.89, P = 0.002). Conclusions. Combination of RT-PCR assays for MN/CA9 and PSMA provides a se nsitive blood test for molecular detection of clear cell carcinoma of the k idney and its potential for vascular invasion. Further testing of this assa y will be required to evaluate its efficacy in the diagnosis, screening, an d follow-up of patients with kidney cancer. UROLOGY 56: 393-398, 2000. (C) 2000, Elsevier Science Inc.