Background :
Telomerase has a leading role as a potential enzyme responsible for tumorigenesis and longevity. Telomerase is a ribonucleoprotein that synthesizes a specific repeating nucleotide sequence onto the ends of telomeres. This enzyme
is normally present in immortalized cell lines, germ-line tissues, and tumor tissues. We intended to compare the telomerase activity among various types of leukemia to determine the association of telomerase activity and patients status and responsiveness of chemotherapy.
Methods :
Specimens were collected from Jan. 1999 to Oct. 1999 and included the leukemic bone marrow (ALL, AML and CML) and the peripheral blood or bone marrow of normal persons or patients with iron deficiency anemia and immune thrombocytopenic purpura. Telomerase activity was measured by TRAP assay using Telomerase PCR ELISA kit.
Results : Telomerase activities were increased in acute leukemias and relapsed acute leukemia cases, whereas in the cases of complete remission state of acute leukemia, the activity was decreased. Telomerase activity was increased in
leukemias which had high percentage of immature cells, especially more than 70% of blast. Also the activity was decreased in post-chemotherapeutic group, whereas increased in untreated group. There was no significant difference between prognosis of chromosomal abnormalities and telomerase activity.
Conclusion :
These results showed that telomerase activity was increased in acute phase of leukemia, high percentage of immature cells, and chemoresistant group of leukemia.

Keywords: Acute leukemia, Chronic myeloid leukemia, Telomerase activity, TRAP assay