Acute Myeloid Leukemia and Myelodysplastic Syndromes with TP53 Aberrations - A Distinct Stem Cell Disorder

The tumor suppressor p53 exerts pivotal roles in hematopoietic stem cell (HSC) homeostasis. Mutations of the TP53 gene have recently been described in individuals with clonal hematopoiesis conferring substantial risk of developing blood cancers. In patients with acute myeloid leukemia (AML) and myelodysplastic syndromes (MDS), TP53 aberrations-mutations, deletions, and a combination thereof-are encountered at a constant frequency of approximately 10%. These aberrations affect HSCs transforming them into preleukemic stem cells, pinpointing their central role in leukemogenesis. AML and MDS with TP53 aberrations are characterized by complex chromosomal aberrations. Respective patients experience a dismal long-term outcome following treatment with both intensive and nonintensive regimens including novel agents like venetoclax combinations or even allogeneic HSC transplantation. However, according to the 2016 WHO classification, AML and MDS with TP53 aberrations are still regarded as separate disease entities. On the basis of their common biological and clinical features, we propose to classify AML and MDS with TP53 aberrations as a single, distinct stem cell disorder with a unique genetic make-up, comparable with the WHO classification of "AML with recurrent genetic abnormalities." This approach will have implications for basic and translational research endeavors, aid in harmonization of current treatment strategies, and facilitate the development of master trials targeting a common deleterious driver event.