In the tumour-bearing tibia, administration of Sema3A (0.7 mg/kg/2-weekly) enhanced bone volume (Fig. 1C, % BV/TV, 96% ± 30, p < 0.05) and showed a trend towards, reduced osteoclast number (Fig. 1D, Oc.N/BS, left panel) and activity (Fig. 1D, Oc.S/BS, right panel) and increased osteoblast number (Fig. 1E Ob.N/BS, left panel) and active surface (Fig. 1E, Ob.S/BS, right panel). Here, SEMA3A is linked to neoplasm.