Granulocyte macrophage colony-stimulating factor (GM-CSF, also named CSF2) is one of hematopoietic cytokine family and its levels significantly elevated in the lesions of patients and rodents with colitis.6,7 In accordance with this, GM-CSF-deficient mice were more susceptible to DSS-induced colitis, as shown by more weight loss and severe diarrhea and by upregulation of proinflammatory mediator production.8 The role of GM-CSF in CAC development, however, is largely unknown. The gene discussed is CSF2; the disease is colitis.