Telomerase activity and cytokeratin 20 as markers for the detection and followup of transitional cell carcinoma: An unfulfilled promise

Purpose: Telomerase activity compensates for the erosion of chromosomes and it has been detected in a wide variety of human tumors. Cytokeratin 20, an intermediate filament of epithelial cells, is expressed particularly in th e urinary tract. These 2 molecules are candidates to become markers for the detection and followup of bladder carcinoma. We evaluate whether each mole cule may serve as a potential marker and whether the 2 combined would impro ve the detection or followup of bladder carcinoma in a noninvasive manner. Materials and Methods: We obtained 44 morning urine samples from patients w ith transitional cell carcinoma patients and 26 from age matched patients w ith a wide variety of clinical disorders but no malignancy of any kind. A t elomerase polymerase chain reaction-enzyme-linked immunosorbent assay kit w as used to determine telomerase activity and cytokeratin 20 expression was determined by nested reverse transcriptase-polymerase chain reaction. Results: All samples tested positive for cytokeratin 8 expression, which ve rified epithelial cells in the urine samples. Of the 44 transitional cell c arcinoma cases of all stages and grades 37 (84.1%) were positive for telome rase activity, 36 (81.8%) were positive for cytokeratin 20 expression and 6 5.9% were double positive. Of the 29 controls with various clinical conditi ons other that malignancy 22 (75.9%) were positive for telomerase activity, 13 (44.83%) were positive for cytokeratin 20 expression and 34.6% were dou ble positive. Conclusions: Telomerase activity and cytokeratin 20 expression are not spec ific for malignancy and may be detected in many nonmalignant pathological c onditions. Therefore, their use as potential markers of bladder carcinoma s hould be carefully reevaluated.