CXCL12 (SDF-1) and CXCL13 (BLC) and their respective receptors CXCR4 and CXCR5 have been implicated in tumor growth, metastasis, and are critical for the regulation of the tumor microenvironment in multiple cancer sub-types as a component of the tumor “Immunome” (3, 83–85). The gene discussed is CXCL12; the disease is cancer.