Cytokeratin shedding into the urine was measured using an enzyme-linked immunosorbent assay in 154 individuals. Samples include urines of normal controls, patients with urological conditions other than bladder cancer and bladder cancer patients. The assay results reflect the potential value of cytokeratin shedding in urine as a new urinary marker for bladder cancer. A 94% sensitivity for patients with squamous cell carcinoma of the bladder suggested the importance of using antibodies prepared against cytokeratin extracted from the same cell type of carcinoma as that to be detected. The relatively low sensitivity shown while detecting transitional cell carcinoma patients and the relatively low degree of assay specificity suggested the use of a panel of monoclonal antibodies specific to various types of cytokeratins of bladder carcinoma.

The main distinctive feature of carcinoma in schistosomal bladder is keratinized squamous cell carcinoma. Keratins/cytokeratins constitute a multigeneic family of structurally related polypeptide markers for the malignant state of epithelial cells. A monoclonal antibody (UNME/K1) regognizing keratins associated with squamous cell carcinoma of the human urinary bladder was generated at the Urology and Nephrology Center, Mansoura, Egypt (UNME), by fusion of spleenocytes from a BALB/c mouse immunized with a keratin extract (K1) of human squamous cell carcinoma and P3X63Ag8/U1 syngeneic myeloma cells. UNME/K1 was purified by a protein-A affinity column and was of the IgG2a type, as determined by immunoelectrophoresis and gel diffusion techniques. When tested against keratins of different types of urinary bladder tumors using enzym linked immunosorbent assay (ELISA), UNME/K1 reacted only with the high molecular weight keratin of squamous cell carcinoma and showed selectivity towards specific histopathological grades of tumors.

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.