Clinical practice and mechanism of endocrinological adverse events associated with immune checkpoint inhibitors

Immune checkpoint inhibitors, used for cancer immunotherapy, show anti-tumor effects through T cell activations. Monoclonal antibodies against cytotoxic T lymphocyte antigen-4 (CTLA-4), programmed cell death (PD)-1, or PD-ligand 1 which is a ligand of PD-1 have been shown to be effective in the treatments of advanced cancers including malignant melanoma, non-small cell lung cancer, and renal cell carcinoma. However, these drugs also have immune-related adverse events (irAEs). The irAEs, which have unique characteristics different from those seen in conventional cytotoxic anti-tumor medicines, are observed in the several tissues such as skin, gastrointestinal tract, liver, lung, muscle, nerve and endocrine systems. To safely use immune checkpoint inhibitors, it is quite important to understand the characteristics of irAEs and to manage them in clinical practice. In this review, we focus on clinical characteristics and pathogenesis of adverse events in the pituitary gland.