Consistent with the in vitro data in Fig. 6, ZA strongly inhibited of osteoclastogenesis of the Gr-1+/CD11b+cells of ZA-treated and non-treated control mice, as shown by a 40% reduction in the number of TRAP+cells formed in the Gr-1+/CD11b+cultures of control vs. ZA-treated tumor-bearing mice (42.4±4.0 vs. 25.6±3.5 osteoclasts per 100× field, p<0.01, Fig. 7). This evidence concerns the gene ACP5 and neoplasm.