Given the established literature behind CSF2/GM-CSF and LIF involvement in macrophage biology,36,37 we isolated primary monocytes from peripheral blood mononuclear cells (PBMCs) from healthy donors, differentiated them into macrophages and then performed a migration assay using conditioned medium (CM) to ask if cancer cell - CAF direct CM was sufficient to increase macrophage attraction. The gene discussed is CSF2; the disease is cancer.