CXCR4 and colorectal cancer: Buhrmann and co-workers showed that RES inhibited the TNF-β-induced EMT as demonstrated by suppressing EMT factors (up-modulating vimentin and slug, down-modulating E-cadherin) in colorectal cancer cells through preventing the FAK/NF-κB activation as proved by down-regulation of MMP-9 and C-X-C motif chemokine receptor 4 (CXCR4) which are the NF-κB-dependent of tumor-promoting factors (17, 18).