Proposed model of the interaction of TCL1A expression with TET2 CHIP clonal expansion. In TET2-mutated HSC clones, TCL1A protein expression is enhanced due to increased TCL1A promoter accessibility, promoting expansion of the clone (left panel). The germline rs2887399 TCL1A variant limits promoter accessibility, abrogating increased TCL1A protein expression and reducing expansion of the TET2 clone (right panel). Reprinted with permission from Springer Nature. Weinstock JS et al. Nature. 2023;616(7958):755-763.