This must necessarily lead to an organotropism; e.g., breast cancer cells express high levels of CXCR4 and CCR7, which are responsible for the metastasis formation in LN, lung, liver, and KM, as these organs are rich in corresponding ligands CXCL12 and CCL21 [Chambers3471]. The gene discussed is CXCR4; the disease is breast carcinoma.