Difficulties to clarify the role of Lcn2 might be related to its different iron-unbound apo-lipocalin-2 and iron-bound, immune suppressive holo-lipocalin-2 form, which may have opposite functions, such as infection defense (iron depletion), wound healing (iron release) or tumor progression (iron release) [39, 41]. The gene discussed is LCN2; the disease is infection.