Under the conditions of chronic inflammation or cancer, GM-CSF, G-CSF, M-CSF, tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, transforming growth factor (TGF)-β and IL-10 are constantly secreted, leading to the alteration of myelopoiesis and generation of myeloid-derived suppressor cells (MDSC) [30,31,32]. Here, CSF1 is linked to cancer.