Furthermore, we analysed the relationship between IDO1, IDO2, TDO2 and IL4I1 expression and some clinical features, such as advanced stage, bilateral ovarian carcinoma, lymph node metastasis, distant organ metastasis, abnormal cytology, tumour rupture, complications (endometriosis or thrombosis), cancer recurrence, chemotherapy drug resistance and death. Here, IDO1 is linked to cancer.