PRAME mRNA expression in newly diagnosed acute myeloid leukemia patients and its application to monitoring minimal residual disease / 中华血液学杂志

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the expression level of preferentially expressed antigen of melanoma (PRAME) mRNA in newly diagnosed acute myeloid leukemia (AML) patients and evaluate its usefulness for detecting minimal residual disease (MRD).</p><p><b>METHODS</b>PRAME mRNA levels were detected in bone marrow samples from 142 newly diagnosed AML patients (72 of them didn't express any specific fusion gene) by TaqMan based real-time quantitative PCR methods, and were serially monitored in 60 bone marrow samples from 9 follow-up patients (2 of them without specific fusion gene), including 3 in continuous complete remission, 6 in hematological relapse. Bone marrow samples from 22 bone marrow donors (NBM) were served as normal controls. Samples from 7 AML1-ETO (+) M2 patients were detected for AML1-ETO mRNA simultaneously. abl was selected as control gene, PRAME and AML1-ETO mRNA levels were expressed by their copies/abl copies in percentage.</p><p><b>RESULTS</b>All NBM samples expressed PRAME mRNA and the upper limit was 0.28%. For all newly diagnosed AML patients, median PRAME mRNA level was 3.97% (0.00%-714.97%), 76.8% of them was higher than 0.28%, 54.9% had over 1-log increasing and 26.1% had over 2-log increasing. For patients without specific fusion gene, median PRAME mRNA level was 0.60% (0.00%-408.72%), 56.3% of them was over 0.28%, 32.4% and 11.3% had over 1-log and 2-log increasing, respectively. There was a significant difference in PRAME mRNA levels between subtypes of AML patients (P<0.01). AML1-ETO (+) M2 patients expressed the highest levels (all P<0.01), followed by acute promyelocytic leukemia patients with S type PML-RAR alpha fusion gene. PRAME and AML1-ETO mRNA levels of follow up patients displayed similar kinetic patterns, and correlated well in 43 follow up samples (r=0.88, P<0.01). PRAME mRNA levels in 3 hematological relapsed patients increased above 0.28% 1-4 months ahead relapse, and in other 3 relapsed patients the levels never decreased to normal range even in remission.</p><p><b>CONCLUSIONS</b>PRAME mRNA could be used to monitor MRD for AML patients with higher than normal levels, and it increases over or persistently higher than normal range predicts hematological relapse.</p>