Ups and downs of CHIP

In this issue of Blood, Berger et al present a longitudinal study of the clonal trajectory of preleukemic mutations in patients who developed therapy-related myeloid neoplasms (t-MNs) after autologous stem-cell transplantation. The authors show that t-MN driver mutations are often detectable as clonal hematopoiesis of indeterminate potential (CHIP) many years before patients develop t-MNs, and they demonstrate complicated patterns of clonal expansion and evolution over time, leading to the development of t-MNs.¹