Lipocalin-2 abundantly secreted from JAK2V617F⁺ cells confers growth advantage to MPN cells. (A) Schematic representation of the following experiments. Murine bone marrow c-Kit⁺ cells were retrovirally transduced with JAK2V617F followed by shRNA against Lcn2 or control shRNA and transplanted into sublethally irradiated mice. (B) Repopulated GFP⁺ cells within bone marrow mononuclear cells were analyzed 6 weeks after transplantation. Three mice were analyzed for each shRNA. (C) Proposed mechanisms whereby JAK2V617F⁺ clones induce paracrine DNA damage and acquire clonal dominance via secretion of lipocalin-2.