IDO2 and testicular germ cell tumor: While high expression of IDO-2 was associated with worse prognosis in three cancer types, namely clear cell renal cancer, papillary renal cancer, and testicular germ cell tumor, it was associated with better prognosis in six cancer types, namely cervical cancer, head-neck squamous cell cancer, mesothelioma, pancreatic cancer, sarcoma, and skin melanoma (Supplementary Figure 3).