Figure 1.

Preleukemic burden is highly variable in acute myeloid leukemia (AML) patients. (A) Preleukemic burden is defined as the percentage of hematopoietic stem cells (HSCs) in an AML patient that harbor at least the earliest preleukemic mutation. This diagram depicts the preleukemic phase of evolution with the acquisition of three distinct mutations represented by three distinct colors (blue, orange, and purple). Eventually, the first mutation (blue) is present in every HSC, leading to a preleukemic burden of 100%. (B) This diagram depicts the acquisition of the same three mutations shown in panel (A) but the resulting HSCs fail to expand. In this scenario, only a minority of the HSCs harbor mutations, and therefore, the preleukemic burden is low.