Telomerase expression in uveal melanoma

Background/aims-Accumulating evidence indicates that telomerase activity is repressed in normal human somatic cells but reactivated in cancers and imm ortal cells, suggesting that activation of telomerase activity has a role i n carcinogenesis and immortalisation. To date, telomerase in uveal melanoma and, whether, it may have a role in the development or progression of thes e tumours has not been described. The expression patterns and the activity of telomerase were investigated in 14 uveal melanoma and these results were correlated with histological and immunohistological features of these tumo urs. Methods-A modified PCR based telomeric repeat amplification protocol (TRAP) assay was used to demonstrate telomerase activity in 14 uveal melanomas. I n addition, in situ hybridisation was used to demonstrate the expression pa ttern of the telomerase RNA component (hTR) at the single cell level in eig ht of these globes. Results-The TRAP assay revealed moderate telomerase activity in all uveal m elanomas examined. In situ hybridisation visualised a moderate to high upre gulation of hTR in the melanoma cells but not in the admired reactive cells . There was no correlation among tumour location, cell type, or growth frac tion and the amount of telomerase activity. In addition, the cells of the g erminative zone of the lens demonstrated a strong hTR expression. Conclusion-Telomerase activity is upregulated in uveal melanomas. The expre ssion of hTR was located to the tumour cells and not the reactive tumour in filtrating cells. Strong telomerase expression was also demonstrated in cel ls of the germinative zone of the lens.