The Expression and Clinical Significance of PRAME Gene in Acute Leukemia.

Objective To investigate the expression of PRAME (preferentially expressed antigen of melanoma) gene in acute leukemia and its clinical significance in monitoring prognosis, detecting minimal residual disease (MRD) and gene immunotherapy.

Methods The expression of PRAME gene mRNA in bone marrow mononuclear cells is measured by reverse transcriptase polymerase chain reaction in 34 patients with acute leukemia and 12 bone marrow samples of health donors. The relationships between PRAME gene expressions and some clinical data, such as gender, age, white blood count, leukemic immunophenotype, the percentage of blast cells, and the karyotype of chromosome, were also estimated.

Results PRAME gene was expressed in 38.2% of all the patients, 40.7% of all the AML patients, which was higher than the 28.6% of ALL patients (p >0.05). There was no expression of PRAME gene in healthy donors. In all the sub phenotypes of AML, the expressive rate of PRAME gene in M₃ patients is 80%, which is higher than that in M₂ (33.3%) and in M₅ (28.6%). The expressive rate of PRAME gene was also positively correlated with the expression of CD15, CD33, and the abnormality in the karyotype of chromosome, but not correlated with age, gender, white blood count and percentage of blast cell in bone marrow.

Conclusion PRAME gene is highly expressed in acute leukemia, and could be regarded as a useful tool for monitoring MRD. Differential expression in acute leukemia patients vs. healthy donors suggests that the immunogenic antigens PRAME are potential candidates for immunotherapy in acute leukemia.