Further, the overexpression and knockdown efficiency of IDO1 in ovarian cancer cell lines were verified by qRT-PCR and Western blot (Additional file 1: Fig. S6a, b). Then, endothelial cells were treated with EVs obtained from IDO1-overexpression and –knockdown ovarian cancer cells to perform tube formation and wound healing assay. Here, IDO1 is linked to ovarian carcinoma.