CXCR4 and lung carcinoma: According to Li et al., a higher expression level of C-X-C motif chemokine 12 (CXCL12) which was observed in the CAFs (when compared to normal fibroblasts) facilitated lung cancer cell proliferation and drug resistance by upregulating the expression of receptor CXCR4 of lung cancer cells which subsequently elevated the expression of NF-κB and Bcl-xL [8].