ADORA2A and cancer: Several antagonists have been in different phases of clinical trials for cancer treatment, and many of these are mixed A2AR/A2BR antagonists such as AB928 (Phase 1, lung cancer, NCT03846310; Phase 1, breast and ovarian cancer, NCT03719326; Phase 1, gastrointestinal cancer, NCT03720678; Phase 1, advanced cancer, NCT03629756), PBF-1129 (Phase 1, non-small-cell lung cancer, NCT03274479), and theophylline.