Correlation between bone marrow activity on F-18 FDG PET/CT and JAK2V617F mutation in myeloproliferative neoplasm

Objectives JAK2V617F (JAK2) mutation, a change of valine to phenylalanine at the 617 position of Janus kinase 2, is known to show an inherent tendency for poor prognosis in myeloproliferative neoplasms (MPNs). The objective of this study was to investigate the relationship between F-18 FDG bone marrow uptake and JAK2 mutation in patients with MPNs.

Methods Sixteen patients (mean age: 57y, range: 32-79y) diagnosed with MPNs from May 2007 to July 2010 were enrolled; 7 essential thrombocythemia (ET), 5 hypereosinophilic syndrome (HES), 2 primary myelofibrosis (PMF), 1 polycythemia vera (PV), and 1 unclassifiable MPN (MPN-u). All patients underwent FDG PET/CT, hematologic tests, and bone marrow biopsy. FDG uptake was semi-quantitatively assessed using mean standardized uptake values (SUV) in the lower thoracic and lumbar vertebrae, spleen and liver. Differences in bone marrow to liver uptake ratio (SUV_BM/L), spleen to liver uptake ratio (SUV_Sp/L), and hematologic parameters according to the presence of JAK2 mutation were evaluated using Mann-Whitney U test.

Results JAK2 mutation was positive in 7 patients and negative in 9 patients. Among age, sex, SUV_BM/L, SUV_Sp/L, and hematological parameters, only SUV_BM/L and neutroplil count (x10³/mm³) were significantly higher in patients with JAK2 mutation; 1.22±0.15 vs. 0.70±0.14 in SUV_BM/L (p<0.001), 8.0±4.0 vs. 3.6±1.9 in neutrophil count (p=0.013). SUV_BM/L over 0.9 could precisely predict the presence of JAK2 mutation (sensitivity: 100%, specificity: 100%, area under ROC curve: 1.000), followed by neutrophil count (sensitivity: 71%, specificity: 100%, area under ROC curve: 0.873).

Conclusions In MPNs, JAK2 mutation strongly correlated with bone marrow FDG activity. F-18 FDG PET can be used for a non-invasive imaging modality to predict prognosis in patients with MPNs