Previous results have shown rhCNB promoted cytokines production and stimulated the expression of the surface molecules as an immune-stimulatory protein,and it could be a potential anti-cancer drug.Recent results revealed exogenous rhCNB was internalized into the tumour cells by TLR4 receptor complex.But it remains unknown whether the anti-tumoral and immunomodulatory function of rhCNB is mediated by Toll-like receptor 4.Here,we reported it is mediated by TLR4 that rhCNB up-regulated the tumor-related cytokines expression and secretion,promoted the increase of the surface costimulatory molecules of antigen presenting cells in vitro.In the same way,rhCNB also enhanced the antigen presenting capacity of peritoneal macrophages,and increased CTL proportion in splenocytes in vivo.Subcutaneous administration of mice with rhCNB resulted in an about 50%reduction of tumor growth in wild type C57 mice,but a slight increase in TLR4-KO mice.These results suggested the anti-tumoral effects of rhCNB are mediated by TLR4 receptor.It is very important for further understanding and development of rhCNB as an anti-cancer drug.