According to Asano et al. [11], the diagnostic criteria for a G-CSF-producing tumor are (1) an increase in peripheral blood white blood cells, mainly mature neutrophils, (2) elevation of serum G-CSF, (3) an increase in neutrophils in tumor-transplanted nude mice, (4) reduction or disappearance of (1), (2), and (3) by tumor excision or treatment, and (5) CSF activity in the culture supernatant of tumor extract. The gene discussed is CSF3; the disease is neoplasm.