Telomerase in urological malignancy

Abstract

Purpose: Telomerase is a ribonucleoprotein enzyme that compensates for the progressive erosion of chromosomal ends, called telomeres. In most somatic cells telomerase expression is repressed and telomeres progressively shorten after each cell division, causing cell senescence. Conversely telomerase is active in most human cancers, maintaining the integrity of chromosome ends and representing an important step in cell immortalization and carcinogenesis. The large and increasing interest in telomerase was motivated by the demonstration that more than 90% of human cancers are telomerase positive, whereas most normal tissues or benign tumors contained low or undetectable telomerase activity. We addressed the most recent data on telomerase detection in urological malignancy. Approaches to telomerase inhibition as a future anti-cancer therapy are also discussed.

Materials and methods: We comprehensively reviewed the most recent and significant publications in this field using current issues of specific journals and a MEDLINE search.

Results: Telomerase is often expressed in bladder (90%), prostate (80%) and renal (69%) carcinoma. A variable but significant percent of normal tissues from tumor adjacent zones or noncancer samples are positive for telomerase. The clinical role of telomerase is still questionable in renal cancer, while important insights into the diagnostic role of telomerase in bladder and prostate carcinoma are increasing. Telomerase detection in exfoliated cells collected with urine or bladder washings seems a promising tool for the diagnosis and management of bladder cancer.

Conclusions: Larger perspective studies of larger groups of patients are required to discover an appropriate role for telomerase when assessing these tumors. The improvement of quantitative methods to evaluate the expression of telomerase is a cornerstone in the complete clarification of the clinical relevance of telomerase.