Telomeres are specific structures found at the end of chromosomes in eukaryotes. In human chromosomes, the telomeres consist of thousands of copies of 6 base repeats (TTAGGG)(1-3). It has been suggested that telomeres protect chromosome ends since damaged chromosomes lacking telomeres undergo fusion, rearrangement and translocation (2). In somatic cells, telomere length is progressively shortened with each cell division both in vivo and in vitro (4-7) due to the inability of the DNA polymerase complex to synthesize the very 5' end of the lagging strand (8,9).
Telomerase is a ribonucleoprotein that synthesizes and directs the telomeric repeats onto the 3' end of existing telomeres using its RNA component as a template (10-14). Telomerase activity has been shown to be specifically expressed in immortal cells, cancer and germ cells (15,16) where it compensates for telomere shortening during DNA replication and thus stabilizes telomere length (7,17). These observations have led to a hypothesis that telomere length may function as a "mitotic clock" to sense the number of cell divisions and eventually signal replicative senescence or programmed cell death when a critical telomere length is achieved. Therefore, expression of telomerase activity in cancer cells may be a necessary and essential step for tumor development and progression (16,18-20). The causal relationship between expression of telomerase and telomere length stabilization and the extension of the life span of the human cell has recently been reported (21).
The development of a sensitive and efficient PCR-based telomerase activity detection method, TRAP (Telomeric Repeat Amplification Protocol)(15, 22), has made possible large scale surveys of telomerase activity in human cells and tissues (15, 23-29). To date, telomerase activity has been detected in over 85% of all tumors tested spanning more than 20 different types of cancers (30-31).
The TRAPEZE® ELISA Kit provides the reagents necessary for performing the TRAP assay followed by ELISA detection of telomerase activity in cell/tissue samples.