Compared with CTRL, the BM niche of PV patients presented increased levels of inflammatory cytokines and angiogenesis- and hematopoiesis-related factors, including CCL2, CCL5, CXCL8, CXCL10, CXCL12, GM-CSF, HGF, IFN-γ, IL-1β, IL-6Ra, IL-12p70, IL-17a, IL-18, M-CSF, TNF-α, VEGF, and VEGF-R2 (Figure 1 and Table S5). Here, CCL2 is linked to acquired polycythemia vera.