CTLA4 and hypophysitis: Hypophysitis is rare in the population who have not received ICIs but hypophysitis occurs up to 10% in the patients who receive anti-CTLA-4 therapy.445 Pituitary glands also expressed CTLA-4 and these may become the targets of CTLA-4 antibody which explain the high incidence of hypophysitis in the patients receiving CTLA-4 blockades.