When fibroblasts were cultured in IL-1α rich CM, this led to the release of cytokines and pro-tumour factors such as IL-8, granulocyte-macrophage colony-stimulating factor (GM-CSF), monocyte chemoattractant protein-1 (MCP-1) and hepatocyte growth factor (HGF), i.e. acquisition of an “activated CAF phenotype” which subsequently promoted cancer cell migration in Boyden chamber assays (23). Here, CSF2 is linked to cancer.