In CD34+ cells of JAK2 positive ET subjects, a largely increased gene expression was observed for CRIP1 and GADD45B, in PV subjects for GLRX, IFI16, LAMP1, in PMF subjects for CPNE3, APEX1, KDM1A, while in JAK2 negative MPN subjects for CIB1, NBPF10 and GPR160. After hierarchical clustering, the arrays of statistically significant genes largely demonstrated tendency to stay gathered within the examined 4 MPN groups. The gene discussed is GADD45B; the disease is acquired polycythemia vera.