CXCR2 and neoplasm: Furthermore, we found the expressions of CXCL1 and its receptor CXCR2 were significantly increased 30 min after 8 Gy of radiation in KYSE-150 and KYSE-30, which may cause a constitutively activated CXCL1/CXCR2 signaling in tumor cells (Figures 1d and e).