CXCR1 and neoplasm: For example, overexpression of CXCR4 in NK cells improved tumor eradication of U87-MG glioblastoma secreting CXCL12.307 Migration of human primary NK cells to CXCR1, CXCR2, and CXCR4 ligands was reported.197 However, CXCR4 is also overexpressed in more than 23 human cancers and contributes to tumor growth, angiogenesis, and metastasis.