While Musolino et al. reported increased FGF-b levels in PV, ET, and PMF [36], Vaidya et al. found FGF-b—together with IL-1β, IL-1RA, IL-2R, EGF, IL-10, FGF-b, IL-12, IFN-α, and RANTES—to be particularly elevated in PMF when compared to PV patients [38]. This evidence concerns the gene FGF2 and acquired polycythemia vera.