Telomerase activity in uveal melanomas

Background: The maximum number of cell divisions of a certain cell populati on is genetically fixed so that aging cells become non-dividing (senescent) at least. This replicative life span, also known as "Hayflick limit", is p robably defined by a "critical" length of the telomeres. Telomeres are spec ial DNA-sequences located at the four ends of the chromosomes which are sho rtened with each cell cycle. Cells of most, but not all malignant tumours h ave been shown to reactivate the enzyme telomerase so that telomeres can be reconstructed, "Hayflick limit" can be overcome, and unlimited cell divisi on can be established. This study was undertaken to elucidate whether telom erase reactivation is used by uveal melanoma cells. Materials and Methods: Fresh tumour tissue was removed from 10 untreated uv eal melanomas after enucleation. Telomerase activity was determined using a PCR ELISA according to the Telomeric Repeat Amplification Protocol (TRAP). Normal tissue of the skin and the conjunctiva served as control. Result: Telomerase activity was detectable in 90% of the investigated uveal melanomas. All control specimens were telomerase negative. Conclusions: Uveal melanoma growth seems to depend on telomerase reactivati on. Thus, telomerase inhibition could offer a new principle for uveal melan oma therapy in the future.