It has been reported that IDO1 may have a pro-angiogenic role in many cancer types [15] and, according to Zhang et al. [16], high IDO1 levels activate the IL-6/STAT3/VEGF-A pathway in bladder cancer cells, which contributes to the activation of the co-cultured endothelium. The gene discussed is IDO1; the disease is urinary bladder carcinoma.