To objectively classify G-CSF-producing cancer, Asano proposed four diagnostic criteria: (a) leukocytosis linked to malignancy that cannot be better explained by other causes, (b) elevated serum G-CSF levels, (c) a decrease in leukocyte and serum G-CSF count post tumour resection, and finally, and (d) immunohistological confirmation of G-CSF production within the tumour. The gene discussed is CSF3; the disease is neoplasm.