Feasibility of using the combined MDS-EVI1/EVI1 gene expression as an alternative molecular marker in acute myeloid leukemia: a report of four cases

To establish an additional marker for polymerase chain reaction (PCR)-based measurement of minimal residual disease (MRD) detection in acute myeloid leukemia (AML), the expression level of the combined MDS1-EVI1 and EVI1 gene was quantified by real-time reverse transcription PCR (RT-PCR) in four AML cases at initial presentation and as a follow-up marker during anti-leukemic therapy. Quantification of the MDS1-EVI1/EVI1 gene expression correlated closely to the clinical course of the disease in all four cases. A hematologic complete remission was accompanied by a reduction of MDS1-EVI1/ EVI1 expression levels of at least 2 log while persistent leukemia was reflected by an MDS1-EVI1/ EVI1 expression in the range of the primary diagnostic sample. After achieving a complete cytomorphologic remission, three patients relapsed after 154, 210, and 280 days, respectively. Molecular relapse was detected on the basis of increasing expression levels of MDS1-EVI/EVI 29, 36, and 93 days before hematologic manifestation. In conclusion, the combined MDS-EVI1/EVI1 gene may serve as an alternative MRD marker in AML, especially in samples where other specific markers are lacking.