ATP and other adenine nucleotides have antitumor effects via the activation of the P2Y1 receptor (P2Y1R) subtype [1,2], whereas adenosine induces cancer cell proliferation and growth of many types of tumors via the activation of the A2B adenosine receptor (AR) [3,4,5,6,7,8,9,10]. Here, ADORA2B is linked to cancer.