This study investigates clonal hematopoiesis and its association with blood cancer risk, using blood DNA sequencing data from 12,380 individuals. Clonal hematopoiesis, characterized by somatic mutations in genes such as DNMT3A, ASXL1, and TET2, was observed in 10% of individuals over 65 years old but only 1% in those under 50. These mutations were strongly linked to an increased risk of hematologic cancer, with a hazard ratio of 12.9. The study also found that clonal hematopoiesis often precedes cancer diagnosis by several months, suggesting that these mutations may represent early events in cancer development. The research highlights the importance of detecting clonal hematopoiesis through DNA sequencing, as it is increasingly common with age and is associated with higher risks of hematologic cancer and mortality. The findings suggest that mutations in certain genes may be early markers of hematologic cancer, even in seemingly healthy individuals. The study also provides insights into the genetic relationships between leukemia and earlier clonal expansions, showing that some cancers may originate from pre-existing clones. Overall, the study underscores the potential of DNA sequencing to identify early risk factors for blood cancers and to inform strategies for early detection and prevention.This study investigates clonal hematopoiesis and its association with blood cancer risk, using blood DNA sequencing data from 12,380 individuals. Clonal hematopoiesis, characterized by somatic mutations in genes such as DNMT3A, ASXL1, and TET2, was observed in 10% of individuals over 65 years old but only 1% in those under 50. These mutations were strongly linked to an increased risk of hematologic cancer, with a hazard ratio of 12.9. The study also found that clonal hematopoiesis often precedes cancer diagnosis by several months, suggesting that these mutations may represent early events in cancer development. The research highlights the importance of detecting clonal hematopoiesis through DNA sequencing, as it is increasingly common with age and is associated with higher risks of hematologic cancer and mortality. The findings suggest that mutations in certain genes may be early markers of hematologic cancer, even in seemingly healthy individuals. The study also provides insights into the genetic relationships between leukemia and earlier clonal expansions, showing that some cancers may originate from pre-existing clones. Overall, the study underscores the potential of DNA sequencing to identify early risk factors for blood cancers and to inform strategies for early detection and prevention.