IDO1/TDO expression was found to be positively linked with aquaporin expression, suggesting that IDO1/TDO may play a role in glioma cell motility [33]. Comparing these bladder cancer cells to the control group, IDO1 knockdown decreased their capacity to migrate, and si-IDO1 transfection dramatically decreased the expression of N-cadherin and vimentin proteins as compared to the si-NC group [26]. This evidence concerns the gene TDO2 and central nervous system cancer.