Cytokeratin shedding in urine as a biological marker for bladder cancer: monoclonal antibody-based evaluation.

Cytokeratin shedding into urine was measured using a double-antibody sandwich enzyme-linked immunosorbent assay (ELISA) in 282 individuals. Samples included urine from normal controls, patients with urogenital conditions and bladder cancer patients. A monoclonal antibody prepared against cytokeratins extracted from a hyperkeratotic low grade squamous cell carcinoma (UNME/K1) was used in the assay. The results indicated reasonable levels of sensitivity (83%), specificity (67%) and overall accuracy (70%) in the detection of bladder cancer. The levels of sensitivity in detecting squamous and transitional cell carcinoma patients were 87 and 73% respectively. The low level of specificity was due to a high frequency of false positive results (55%) within the urogenital controls; this suggests that further immunochemical and immunohistopathological analyses of associated urothelial cytokeratins are required.