Clonal hematopoiesis (CH), where few blood stem cells produce a significant fraction of mature blood cells that are genetically identical, is partly an inevitable feature of aging. Certainly, it is near universal in those older than 60. CH is not itself a disease, but 1%-2% of CH cases progress to acute myeloid leukemia, and it raises the risk of some other types of cancer as well. A total of eight genes are responsible for 95% of CH cases, George Vassiliou told the audience in Saturday’s plenary session at the 2026 Annual Congress of the European Hematology Association (EHA 2026).