Moreover, the myeloid cell-secreted cytokine lipocalin-2 (LCN2) or neutrophil granulocyte-associated lipocalin (NGAL) have often been found to be elevated in PV, ET, and PMF patients as compared to healthy controls, suggesting roles in the fibrotic transformation of the bone marrow microenvironment [64,65,66]. Here, LCN2 is linked to acquired polycythemia vera.