We observed a 19% reduction in the number of TRAP-positive, multinucleated (≥3 nuclei) osteoclasts produced in the presence of MDA-MB-231 breast cancer cells plus EO-231 cells compared to TRAP-positive, multinucleated (≥3 nuclei) osteoclasts produced in the presence of MDA-MB-231 breast cancer cells plus naïve osteoblasts (Figure 4e). The gene discussed is ACP5; the disease is breast cancer.