HLA-E and central nervous system cancer: In healthy tissues, HLA-E expression is low (112), but high HLA-E expression is linked to poor patient outcomes in several cancer types, including gastric cancer (113, 114), colorectal cancer (113), pancreatic cancer (93), breast cancer (94), renal cell carcinoma (115), ovarian cancer (116), and glioma (111, 117), suggesting a dominant impact of NK inhibition on limiting anti-cancer activity.