CXCR4 and gastric cancer: CXCR4 (chemokine receptor type 4): Its expression has been associated with the staging of gastric cancer, being reduced in the majority of gastrointestinal tumors and significantly higher in patients with advanced stages of gastric cancer (Shibuta et al., 1997; Hannelien et al., 2012; Nikzaban et al., 2014).