4T1 tumour-bearing mice had ↑ of NFκB, IL-1β, TNF-α, IDO, COX-2, and iNOS and ↓ of IL-10, Nrf2, and BDNF. CMI treatment ↓ the expression of inflammatory markers and ↑ the expression of IL-10, Nrf2, and BDNF. The gene discussed is IDO1; the disease is neoplasm.