Molecular Minimal Residual Disease Detection in Acute Myeloid Leukemia

Simple Summary: Although the majority of patients with acute myeloid leukemia (AML) reach a morphologic complete remission after high-dose chemotherapy, the majority of them face a relapse within a few years. Detection of residual cells, persisting in a considerably small amount, has shown to be predictive of impending relapse in multiple studies. Whereas the gold standard in minimal residual disease (MRD) detection in AML is currently based on immunophenotypic approaches, the use of molecular MRD testing to predict AML relapse has been explored extensively in recent years. This review aims to provide an overview of the different studies that improve molecular MRD detection in AML, and to describe the limitations and challenges it faces. Initial induction chemotherapy to eradicate the bulk of acute myeloid leukemia (AML) cells results in complete remission (CR) in the majority of patients. However, leukemic cells persisting in the bone marrow below the morphologic threshold remain unaffected and have the potential to proliferate and re-emerge as AML relapse. Detection of minimal/measurable residual disease (MRD) is a promising prognostic marker for AML relapse as it can assess an individual patients' risk profile and evaluate their response to treatment. With the emergence of molecular techniques, such as next generation sequencing (NGS), a more sensitive assessment of molecular MRD markers is available. In recent years, the detection of MRD by molecular assays and its association with AML relapse and survival has been explored and verified in multiple studies. Although most studies show that the presence of MRD leads to a worse clinical outcome, molecular-based methods face several challenges including limited sensitivity/specificity, and a difficult distinction between mutations that are representative of AML rather than clonal hematopoiesis. This review describes the studies that have been performed using molecular-based assays for MRD detection in the context of other MRD detection approaches in AML, and discusses limitations, challenges and opportunities.