G-CSF can promote invasion and metastasis of breast cancer cells by regulating the activities of stromal cells including neutrophils, macrophages, and fibroblasts (Kowanetz et al., 2010; Orecchioni et al., 2013; Samineni et al., 2013; Benesch et al., 2015; Hollmen et al., 2015; Welte et al., 2016). The gene discussed is CSF3; the disease is breast cancer.