Molecular Monitoring of RUNX1-RUNX1T1 Transcript Level in Acute Myeloblastic Leukemias on Treatment

Background. The current approach to treatment of acute myeloblastic leukemia (AML) includes the achievement of maximum tumor reduction and, therefore, eradication of a leukemic clone. The goal of the therapy is to achieve undetectable levels of the target gene, except an isolated molecular rearrangement of RUNX1-RUNX1T1. Aim. To estimate the dynamics of the RUNX1-RUNX1T1 level and relevant clinical manifestations during the monitoring of various stages of the program therapy and after its completion. Methods. The article presents a description of 10 cases of AML with isolated RUNX1-RUNX1T1 expression (n = 4) and the expression in combination with different molecular and cytogenetic abnormalities (n = 6). In addition, a long-term monitoring of the gene expression by quantitative determination of RUNX1-RUNX1T1 using a real-time PCR was presented. Results. The incidence of relapses in a group with a decreased RUNX1-RUNX1T1 expression level of >2 log is 75 % as compared to patients with a less significant reduction of the transcript level (with the relapse incidence equal to 0 %) (p = 0.05). The increase of the RUNX1-RUNX1T1 level against the background of bone marrow remission by more than 1 log coincided with a bone marrow relapse within 5-18 weeks. In addition, long-term persistence of a certain transcript level after the completion of a program therapy without relapse is possible. Conclusion. The study analyzed possible molecular background of different clinical outcomes of long-term persistence of the RUNX1-RUNX1T1 transcript that might lead to an individualized approach to AML patients.