CXCR4 is the predominant receptor for the chemokine ligand CXCL12; overexpression of CXCR4 and CXCL12 is found in several solid cancers, such as CRC, gastric cancer, pancreatic cancer and lung cancer [22,23,24,25,26]. The gene discussed is CXCR4; the disease is lung carcinoma.