Concentration and microsatellite status of plasma DNA for monitoring patients with renal carcinoma

We verified the feasibility of plasma bound method for detecting renal cell carcinoma (RCC) combining the study of plasma DNA concentration and microsatellite alterations (LOH). Plasma DNA concentration was evaluated with real-time PCR in 54 patients with renal neoplasm before surgery and in 20 of these patients during a 26-64 month follow-up. Microsatellite study was performed on tumour tissue DNA of 33 RCC clear cell (RCCcc) and on plasma DNA of 14 RCCcc patients during preoperative and/or follow-up period. Patients had a significantly high (26.4+/-48.3 ng/ml versus controls 3.2+/-1.5 ng/ml; p=0.003) preoperative plasma DNA concentration that decreased after nephrectomy. During follow-up, plasma DNA increased in 12 patients without evidence of neoplasia; 3 patients successively relapsed. Tumour tissue DNA of 25 RCCcc patients (75.8%) displayed microsatellite LOH. Preoperative plasma DNA of 9 patients harboured LOH in 5 cases (55.6%). Augmented plasma DNA of 7 patients displayed LOH in 3 cases (42.9%) at follow-up, and in 1 case preceded the recurrence of disease. Plasma DNA concentration combined with microsatellite LOH in plasma DNA may predict disease recurrence in RCC patients.