The down-regulation expression of TLR-4, Myd88 and TRAF-6 mRNA and protein expression were poorly correlated with severe mucositis, which leads to induction of inflammatory cytokines such tumor necrosis factor- α, IL-1, and IL-6; and, therefore, cannot explain the developed widespread intestinal mucosal injury. The gene discussed is TLR4; the disease is mucositis.