Microsatellite analysis of free tumor DNA in urine, serum, and plasma of patients: a minimally invasive method for the detection of bladder cancer.

Tumor cells may release DNA into circulation, which is subsequently carried as free DNA and enriched in blood and urine. The detection of tumors by microsatellite analysis of free DNA offers a possibility to establish a minimally invasive method for the detection of bladder cancer.We performed microsatellite analysis of free DNA of urine, serum, and plasma in comparison with DNA of lymphocytes and tumors of 40 patients with conspicuous bladder lesions. Six microsatellite markers were used for the detection of alterations on chromosomes 4, 9, and 17.Twenty-six of 36 bladder tumor tissue samples showed alterations. Microsatellite changes matching those in the tumor tissues were detected in at least one of the body fluids in 23 cases.The study indicates that simultaneous and multiple investigations of microsatellite markers on free DNA of urine and blood could have clinical relevance as a minimally invasive method for diagnosis and screening of bladder cancer.