This study demonstrated that treatment with USP8 inhibitor, 9‐ehtyloxyimino9H‐indeno(1,2‐b) pyrazine‐2,3 dicarbonitrile, suppresses ACTH secretion, cell viability, and promotes cell apoptosis in AtT20 cells suggesting that USP8 inhibitor could be a new therapeutic candidate for CD [37]. Here, USP8 is linked to Cowden disease.