[Molecular diagnostics in urologic oncology. Detection of nucleic acids in urine samples]

The goal of molecular diagnostics in oncology is the early diagnosis of malignant disease processes during initial work-up or as part of follow-up. Body fluids serve as the primary material for non-invasive diagnostic methods. Besides actual tumor cells, the examination of urine can yield evidence of secreted proteins or even free nucleic acids. In principle, all of the methods available for the detection of tumor markers in tissue or blood samples can be successfully applied to the examination of urine samples. However, molecular biological examination of urine samples is associated with important problems because the cells in such samples are exposed to significant degradation and regression effects and because certain components of the urine act to inhibit the polymerase chain reaction. The present overview discusses the respective strengths and weakness of the available technology as applied to the diagnosis of urologic malignancies. Experimental studies conducted to date have reported high sensitivities and specificities for molecular diagnostics using urine samples. It is important to note that not only carcinomas of the urinary bladder can be diagnosed from material obtained in urine samples: in fact, the method can be used to diagnose entities such as renal cell and prostate carcinomas and, due to renal filtration of DNA, even non-urologic malignancies. The diagnostic application of these methods, however, remains in an experimental stage and must still clear several hurdles before becoming available for routine clinical use.