To search for the new marker for monitoring and investigating the dynamic changes of telomerase activity during the chemotherapy in patients with acute promyecytic leukemia (APL) and evaluate the correlation between the activity of this enzyme and prognosis, 12 patients with APL were enrolled for this study.

The telomerase activities were studied in the initial stage of presentation and after complete remission achieved with ATRA and other combined chemotherapy induction with TRAP Elisa PCR method. At the same times the effect of the tumor burden, patient’s age, therapeutic measures and the time after achieving complete remission (CR) on the telemerase activity were compared.

The results showed that the bone marrow blast in patients with APL onset had significantly higher telomerase activity (1.96±0.86) in comparison with the normal control group at the same age(0.12±0.04, p<0.01). But when the patients got complete remmision after induction therapy the telemerase activities remarkably decreased and approached to the normal range (0.25±0.35). while the telomerase activity still kept on the higher level in one case after CR, relapse followed soon. No significant difference in telomerase activity could be found no matter how they achieved CR, only with ATRA or ATRA combined chemotherapy, how old the patient was and how long they got into CR.

Our results indicating the telemerase activity could be used as the generalized marker for APL cells. The intensity of the enzyme activity had close relationship with the tumor burden. So the telomerase activity might be the potential marker in monitoring the residual tumor cells, evaluating the therapeutic effect and predicting the prognosis of the patients.

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