The mechanism of indoleamine 2,3-dioxygenase participating in breast cancer immune tolerance / 中国免疫学杂志

ABSTRACT

Objective:To investigate the expression of indoleamine 2,3-dioxygenase and the distribution of Treg cells in breast cancer and tumor draining lymph nodes (TDLNs) and to explore the relationship between them.Methods:26 cases of breast cancer and 10 cases of breast benign diseases were collected from Tianjin medical university cancer hospital.RT-PCR was used to detect the mRNA of IDO in breast cancer,TDLNs,benign diseases and normal breast tissues.Immunohistochemistry was used to detect the expression of IDO and Foxp3 proteins in the same tissues. Results:The mRNA and the percentage of IDO~+ cells [(19.59±7.65)%] in TDLNs were higher than in breast cancer [(13.16±7.82)%] (P<0.05),while in the breast cancer were higher than in benign diseases [(3.24±1.30)%] and normal breast tissue [(2.70±1.53)%] (P<0.05).Expression of IDO protein in breast cancer was associated with tumor clinical stage and lymph nodes metastasis while had no relationship with tumor diameter,ER,PR and Her2 status.The percentage of Foxp3~+ cells in breast cancer [(3.50±1.04)%] was higher than in benign diseases [(0.71±0.42)%] (P<0.05) and normal breast tissue [(0.55±0.34)%],and that of the TDLNs [(6.13±2.31)%] was higher than in breast cancer [(3.50±1.04)%] (P<0.05).The percentage of IDO~+ cells was positive correlated with the distribution of Treg cells in breast cancer(r~2=0.449,P<0.05)and TDLNs (r~2=0.454,P<0.05).Conclusion:Expression of IDO in breast cancer is upregulated.The high level expression of IDO is accompanied by increasing Treg cells in breast cancer and TDLNs,which suggests that breast cancer can recruit Treg cells by expressing IDO to participate the immune tolerance.