In the present study, the targeted downregulation of CXCR4 expression in the MDA-MB-231BA-rfp breast cancer cell line (with a high propensity to metastasize to bone) via RNA interference (RNAi) techniques was performed to analyze the effect of CXCR4 on the ability of cancerous cells to metastasize to the bone, as well as to investigate the underlying mechanisms. The gene discussed is CXCR4; the disease is breast carcinoma.