To further clarify the impact of the CXCL12/CXCR4 interaction on the migration capacity of lung cancer cells in vitro, chemotaxis and the chemotactic invasion response of lung cancer cells to the CXCR4 ligand, CXCL12, were detected following the downregulation of CXCR4 expression. The gene discussed is CXCL12; the disease is lung carcinoma.