Individual risk assessment in MDS in the era of genomic medicine

Progression, transformation, and unusual manifestations of myelodysplastic syndromes and myelodysplastic-myeloproliferative neoplasms: lessons learned from the XIV European Bone Marrow Working Group Course 2019

Disease progression in myelodysplastic syndromes (MDS) and myelodysplastic-myeloproliferative neoplasms (MDS/MPN) is a major source of mortality. The European Bone Marrow Working Group organized a dedicated workshop to address MDS and MDS/MPN progression, and myeloid neoplasms with histiocytic and lymphoblastic outgrowths in 2019 in Frankfurt, Germany. In this report, we summarize clinical, histopathological, and molecular features of 28 cases. Most cases illustrate that prognostic mutational profiles change during follow-up due to accumulation of high-risk mutations in the trunk clone, and that results from repeated molecular testing can often explain the clinical progression, suggesting that regular genetic testing may predict transformation by early detection of aggressive clones. Importantly, identical mutations can be linked to different clinical behaviors or risks of fibrotic progression and/or transformation in a context-dependent manner, i.e., MDS or MDS/MPN. Moreover, the order of mutational acquisition and the involved cell lineages matter. Several cases exemplify that histiocytic outgrowths in myeloid neoplasms are usually accompanied by a more aggressive clinical course and may be considered harbinger of disease progression. Exceptionally, lymphoblastic transformations can be seen. As best estimable, the histiocytic and lymphoblastic compounds in all occasions were clonally related to the myeloid compound and-where studied-displayed genomic alterations of, e.g., transcription factor genes or genes involved in MAPK signaling that might be mechanistically linked to the respective type of non-myeloid outgrowth.

ICUS, IDUS, CHIP and CCUS: Diagnostic Criteria, Separation from MDS and Clinical Implications

Various myeloid neoplasms, including the myelodysplastic syndromes (MDS), bear a certain risk of progression to secondary acute myeloid leukemia (sAML). The evolution from low-risk to high-risk MDS and finally to sAML suggests that leukemogenesis is a multistep process. However, even before an overt neoplasm, such as an MDS, develops, "prediagnostic" clonal conditions may be identified. With the advent of large-scale genomic screens, such conditions may be detected quite frequently and early in apparently healthy individuals. Recent data suggest that these conditions increase with age and are indeed associated with an increased risk of the occurrence of MDS or another myeloid neoplasm. In other patients, unexplained cytopenia may be detected and may precede MDS. More recently, diagnostic criteria for potential pre-MDS conditions, including idiopathic cytopenia of uncertain significance and clonal hematopoiesis with indeterminate potential, have been proposed. The current article provides an overview of pre-MDS states and related criteria through which these conditions can be discriminated from each other and from MDS. In addition, the clinical implications and management of pre-MDS states are discussed.