The allele burden of JAK2 V617F can aid in differential diagnosis of Philadelphia Chromosome-Negative Myeloproliferative Neoplasm

BACKGROUND We aimed to evaluate the feasibility of using the allele burden of Janus kinase 2 (JAK2) V617F as a criterion for discriminating 3 subtypes of Philadelphia chromosome-negative myeloproliferative neoplasm (Ph(-)MPN): polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). METHODS We collected 70 peripheral blood (PB) and 81 bone marrow (BM) samples from patients diagnosed with Ph(-)MPN. Real-time quantitative PCR (RQ-PCR) and Amplification Refractory Mutation System (ARMS) assays were performed for each sample. We compared the allele burden of JAK2 V617F for each subtype of Ph(-)MPN and determined the concordance rates of the results between the 2 tests. RESULTS The JAK2 V617F allele burden differed significantly among the 3 disease categories in both PB (P=0.045) and BM (P=0.011) samples. Subsequent subgroup analysis revealed that the median allele burden of JAK2 V617F for ET (21.71% for PB and 24.95% for BM) was significantly lower than that for PV (56.88% for PB, P=0.047; 72.66% for BM, P=0.003) and PMF (56.16% for PB, P=0.050; 59.04% for BM, P=0.049). Concordance rate between the RQ-PCR and ARMS data was 90.7%. Of the 14 discrepant cases, 12 were RQ-PCR(+)/ARMS(-) and 2 were RQ-PCR(-)/ARMS(+). CONCLUSION The allele burden of JAK2 V617F was significantly lower for ET than that for PV or PMF in both PB and BM samples. The JAK2 V617F allele burden is a diagnostic tool for differentiating PV or PMF from ET.