ADORA2A and neoplasm: ADORA1/A1R, which may inhibit tumor proliferation44 was expressed in a distinct subset of predominantly A2BR-negative tumor cells (24.4%, 0.45 mean-expression), while ADORA2A/A2AR was expressed by 5.3% of tumor cells (0.12 mean-expression), and ADORA3/A3R by only 0.64% of tumor cells (0.01 mean-expression).