Acute myeloid leukemia (AML) describes a heterogenous group of hematological disorders. Cytogenetic and molecular assays have allowed patients' follow up aiming for detection of minimal residual disease, prediction of patients' outcome, in addition to providing the rationale for designing novel molecular-targeted therapeutic strategies. Human telomerase reverse transcriptase (hTERT), encoded by the hTERT gene and the telomerase RNA component (hTERC) genes are frequently amplified in human tumors, which may indicate that the hTERT and the hTERC genes may be target for amplification during the transformation of human malignancies including hematological malignancies. This genetic event has implications in diagnosis, prognosis and therapeutics of cancer. To evaluate the hTERC and hTERT genes as a prognostic marker in patients with AML, hTERC and hTERT gene amplification was studied in 20 adult AML patients using a commercial FISH probes (Kreatech) designated to detect the copy numbers of the genes. They were 12 males and 8 females. Their ages ranged from 16 to 67 years. The patients were further divided into two groups; group I (12 patients) includes newly diagnosed AML patients and group II (8 patients) includes patients taken at 28th day of chemotherapy. The hTERC amplification was detected in 19/21 cases (90.5%). The copy number of the gene ranged from 2-5 copies per interphase cell. For the hTERT gene, the amplification was found in the same percent of the patients. The copy number of the gene ranged from 2-9 copies per interphase cell. On comparing the group I with group II there was a highly statistical significant difference regarding the percent of amplification of both genes. The percent of amplification of hTERT gene was found to be higher among patients with poor outcome of the disease than in patients with good outcome. On the contrary the hTERC gene amplification did not exhibit such a correlation. In conclusion, hTERT and hTERC genes amplification were detected in patients with AML; therefore telomerase can be a good cancer marker which may be involved in carcinogenesis of leukemia. Higher amplification was found in de novo cases than cases in remission which emphasize its role in clinical analysis, disease monitoring and detection of minimal residual disease.
Keywords: Acute Myeloid leukemia, telomerase amplification, hTERC gene, hTERT gene.