JAK2 V617F Clonal Dynamics from Clonal Hematopoiesis to Myeloproliferative Neoplasms: A Systems Biology Review of Digital PCR-Based Molecular Monitoring

Clonal hematopoiesis of indeterminate potential (CHIP) is an age-associated premalignant state defined by somatic mutations in hematopoietic cells at a variant allele frequency (VAF) ≥2% in the absence of overt hematologic malignancy. Among CHIP-associated mutations, JAK2 V617F is of particular interest because it occupies a dual biological and clinical role: it is both the principal driver of BCR::ABL1-negative myeloproliferative neoplasms (MPNs) and a clonal hematopoiesis variant conferring approximately 12-fold cardiovascular risk in selected cohorts, exceeding that reported for common DTA CHIP variants. Quantitative assessment of JAK2 V617F allele burden is therefore clinically relevant across the full disease continuum—from subclinical clonal expansion to MPN diagnosis, prognostic stratification, and therapeutic monitoring—as VAF thresholds correlate with disease phenotype, thrombotic risk, molecular response, and fibrotic progression. Digital PCR platforms, including droplet digital PCR (ddPCR) and chip-based digital PCR, have emerged as highly sensitive and reproducible methods for absolute JAK2 V617F quantification without the need for standard curves, with reported limits of detection as low as 0.01%. In this review, we synthesize current evidence on the molecular biology of JAK2-driven clonal hematopoiesis, the clinical significance of allele burden quantification, and the analytical performance of digital PCR compared with quantitative PCR and next-generation sequencing. We interpret these findings through a systems biology lens that draws together JAK-STAT signaling networks and thrombo-inflammatory pathways including inflammasome-dependent IL-1 signaling, clonal architecture, and bone marrow microenvironmental remodeling. We also discuss published quantitative models in which JAK2 V617F allele burden is treated as a dynamic state variable, while emphasizing that the present review offers a conceptual synthesis rather than a new computational model. We provide a structured comparative synthesis of published digital PCR analytical performance data, a stage-adapted proposal for clinical monitoring, and schematic models to guide future implementation. Overall, the evidence supports digital PCR as a precision tool for monitoring JAK2 V617F clonal dynamics across the CHIP–MPN spectrum, and points to several priorities: assay standardization, harmonized reporting, external quality assessment, and prospective clinical validation.