CSF3 and cancer: Tumor-related leukocytosis is a paraneoplastic syndrome that is rarely observed in patients with nonhematologic malignant tumors [4] and can be caused by the upregulation of granulopoietic cytokines and growth factors, such as G-CSF, granulocyte-macrophage colony-stimulating factor, interleukin (IL)-1, IL-6, and tumor necrosis factor-α [5].