CXCL12 and leukemia: In addition, in aging and leukemia, the relative contribution of the Lepr+Adipoq+Kitl+ AdipoCAR population changes [down in leukemia (Baryawno et al., 2019), up in aging (Zhong et al., 2020)], thereby changing the factors to which HSCs are exposed, such as varying concentrations of ANG-1/2, CXCL12 (Stromal-Derived Factor 1: SDF1), IL7, KITL (Stem Cell Factor: SCF), and SFRP1.