Among them, the chemokine family, including CC (e.g., CCL1, CCL3, CCL5, CCL7, and CCL15), CXC (e.g., CXCL1, CXCL3, CXCL5, and CXCL10), XC (e.g., XCL1 and XCL2), and CX3C (e.g., CX3CL1), plays a pivotal role in tumor development, metastasis, and chemotherapy resistance 30-33. The gene discussed is XCL2; the disease is neoplasm.