Some other microenvironmental factors such as CSF-1, CCL2, IL6, vascular endothelial growth factor (VEGF-A) and platelet-derived growth factor (PDGF) have also been involved in infiltration of monocytes to the tumour sites (Balkwill, 2004; Joyce and Pollard, 2009). The gene discussed is CSF1; the disease is neoplasm.