Fig. 3: IDO expression in high-grade ovarian serous carcinoma.
From: Targeting immune checkpoints in gynecologic cancer: updates & perspectives for pathologists

This high-grade ovarian serous carcinoma (A) strongly expresses the immunosuppressive enzyme indoleamine dioxygenase 2, 3 (IDO) (B). Drugs targeting this enzyme both alone and in combination with checkpoint inhibitors are currently under investigation in a variety of clinical trials.