MPN patients are characterized by a transcriptional signature of increased JAK2 activity regardless of JAK2 genotype. (A) Heatmap representation of differentially expressed genes (FC >3 and FDR <0.01) among MPN patients. A red-blue color scale depicts normalized gene expression levels (red: high; blue: low). Displayed are the top 100 differentially expressed genes derived from a supervised analysis comparing transcript expression in granulocytes from JAK2V617F homozygous mutant granulocytes vs normal subjects. The transcripts encoding JAK2, STAT5B, CD177 (PRV1), and MAPK214 are displayed. (B) GSEA showing enrichment of JAK2 shRNA signature in MPN patients relative to normal subjects regardless of JAK2 mutational status.