Clinical significance of telomerase activity in basal cell carcinomas and in tumour-free surgical margins.

To distinguish the infiltrative from the non-infiltrative basal cell carcinoma (BCC), cell cycle markers are being used to supplement histopathological assessment, and proliferation markers are proving particularly useful. A successful radical therapeutic intervention depends on a clear histopathological diagnosis, especially for the tumour margins. For this purpose we investigated whether proof of telomerase activation is a suitable adjunctive molecular marker. We were also interested in the telomerase activity (TA) of BCC-free margin tissues as a prognostic parameter of relapse. Using PCR-ELISA kits, we found TA in 26/30 (87%) BCC tissues and in 8/25 (32%) of the tumour-free surgical margin tissues. Telomerase levels and the incidence of telomerase-positive tumour tissues are not always associated with positive p53 immunoreactive scores in BCC tissues. But telomerase levels correlate significantly with p53 expression levels. In the Kaplan-Meier curve, patients with telomerase-positive tumour-free surgical margin tissues showed significantly shorter relapse-free periods than patients with telomerase-negative tumour-free margin tissues.