RESUMO
The study was aimed to investigate the expression of preferentially expressed antigen of melanoma (PRAME) gene in adult acute leukemia and its clinical significance. The expression of the PRAME gene of bone marrow was measured by reverse transcriptase polymerase chain reaction (RT-PCR) in 73 adult newly diagnosed acute leukemia patients, 3 relapsed patients, 7 patients with idiopathic thrombocytopenic purpura (ITP) and 8 healthy donors, as well as two AL cell-lines (K562 and U937). The results indicated that PRAME mRNA was expressed in 42.9% AML patients (n=24) and 20% ALL patients (n=4), also in two leukemia cell-lines K562 and U937, but not in eight health donors and seven ITP patients. PRAME expression not correlated to the white blood count, hemoglobin level, platelet count and the percentage of blasts at diagnosis, yet independent of age, sex, and FAB type. PRAME mRNA expression in complete remission group seems much higher than those in partial complete remission group and death group. The increased levels of expression could be found prior to the relapse in one patient being regularly monitored. PRAME gene was overexpressed in adult acute leukemia patients and leukemia cell-lines. It is concluded that the expression of PRAME is an indicator of favorable prognosis and can be a useful tool for monitoring minimal residual disease (MRD) in adult acute leukemia. Differential expression between adult acute leukemia patients and healthy volunteers suggests that the immunogenic antigens PRAME are potential candidates for immunotherapy in adult acute leukemia.
