Figure 4.
SF3B1 clonal dominance modulates ASXL1/JAK2/CBL interplay in MDS/MPN-SF3B1-T. This schematic illustrates the molecular interplay underlying the paradoxical hematologic stability observed in this unique case of SF3B1-mutant MDS/MPN. The dominant SF3B1 p.K700E clone (VAF 40.5%) orchestrates a dual pathogenic cascade: while its spliceosomal dysfunction (via ABCB7/ALAS2 mis-splicing) drives ineffective erythropoiesis, it simultaneously attenuates the leukemogenic potential of the subclonal ASXL1 truncation through erythroid lineage restriction. Concurrently, the JAK2 p.R683G variant exhibits suboptimal kinase activation, which - when coupled with CBL p.R149Q-mediated RAS/MAPK hyperactivation and compensatory JAK2 ubiquitination - generates self-limiting thrombopoiesis. This intricate mutational synergy creates a state of clonal equilibrium, wherein competing oncogenic signals paradoxically maintain disease stability without therapeutic intervention, challenging conventional risk stratification paradigms.
