Tumor cells secrete various factors that stimulate osteoclast-mediated bone resorption, and there are studies showing that IL-1, IL-6, IL-8, tumor necrosis factor (TNF)-α, and transforming growth factor (TGF)-β are secreted by tumor cells and contribute to osteoclast-induced bone resorption [2–4]. The gene discussed is TNF; the disease is neoplasm.