CSF3 and neoplasm: Notably, in brain metastatic sites, the increased presence of neutrophils significantly correlates with the expression of c-Met, which can be activated by its cognate ligand—hepatocyte growth factor (HGF) in tumor cells (113).The elevated activation of the c-Met pathway in brain metastatic cells leads to the upregulation of inflammatory cytokines like G-CSF, GM-CSF, CXCL1, and CXCL2.