Homing of pre-LSCs is specified by Wnt signaling. (A) HoxA9-Meis1a-LKS⁺ pre-LSCs, characterized by active β-catenin signaling, homed 11 μm (median; range, 0-40.4 μm) from osteoblasts (n = 4 biologic replicates). In contrast, HoxA9-Meis1a-GMP (without active β-catenin signaling) pre-LSCs homed 17.6 μm (median; range, 0-56 μm) from osteoblasts (P < .01; n = 4 biologic replicates). HoxA9-Meis1a-GMP that expressed a constitutively active β-catenin homed 8 μm (median; range, 0.5-28 μm, n = 2 biologic replicates) from osteoblasts. P < .01, compared with HoxA9-Meis1a-GMP. (B) β-Catenin^−/− MLL-AF9-GMP pre-LSCs homed 20 μm (median; range, 4-44 μm) from osteoblasts compared with control (β-catenin^fl/fl) MLL-AF9-GMP pre-LSCs, which homed 10 μm (median; range, 4-26 μm) from osteoblasts (P < .01; n = 2 or 3 biologic replicates).