In bone metastatic cancer, T cells are recruited and activated by tumor secreted factors such as PTHrP, interleukin (IL)-7, and IL-8, and recruited T cells can secrete tumor necrosis factor-α (TNF-α) or RANKL to induce bone resorption (15), which allows T cells to also participate in the vicious cycle process. The gene discussed is CXCL8; the disease is neoplasm.