Determination of telomerase activity and telomere length.

Telomerase is an enzyme that has been attracting much attention in recent years because its activities are so central to the processes of malignant transformation. It is a reverse transcriptase enzyme that can synthesize telomeric DNA using its own RNA component as a template. Without telomerase, telomeres will shorten until, at a critical length, cells enter senescence and die. The low level or absence of telomerase activity in most nonneoplastic tissues and somatic cells, and its presence in almost all malignant tumors is thus of great interest for potential diagnostic, prognostic, and therapeutic applications in the management of human cancer. It has been documented that high telomerase activity and short telomere length correlate with poor prognosis in patients with multiple myeloma, and antitelomerase therapy has become a novel therapeutic approach for the disease. Thus, determination of telomerase activity and telomere length is essential in the study of cancer. In this chapter, we provide a standard telomeric repeat amplification protocol for telomerase activity assay and a Southern blot terminal restriction fragment protocol for telomere length assay. We also discuss comparison with related assay methods.