CXCL8 and esophageal cancer: However, interleukin 8 is a member of the CXC chemokine family and was originally identified as a chemotactic factor of neutrophils that play an important role in the tumor microenvironment, including in non–small cell lung cancer.35 Monocyte/macrophage infiltration is more common than neutrophils in esophageal cancer and CRC,36 which is consistent with the low concentrations of serum interleukin 8 observed in this study.