[Telomerase and new aspects for tumor biology]

The field of tumor genetics is characterized by a whole string of unsolved questions that affect both the basics of tumorigenesis and the possibilities of using molecular markers at the clinical level. Telomerase, an enzyme that has the capability of unlimitedly maintaining the division of immortal cells, can nowadays be demonstrated with the use of up-to-date molecular biological methods. In vitro experiments have now succeeded in changing normal cells into tumor cells via transfection with telomerase. The regulatory mechanisms and interactions of telomerase are presently the subject of intensive research. Telomerase activity plays a crucial role even in present day diagnostic procedures and the estimation of prognosis for certain tumor types. In comparison with normal tissues, increased telomerase activity in tumor tissues implies therapeutical possibilities with the use of telomerase inhibitors.