ADORA2A and breast cancer: ARs are classically classified into two main groups, α‐AR and β‐AR, both of which are widely distributed in most of mammalian tissues.4 Powe and colleagues performed immunohistochemistry on tissue microarrays to characterize AR expression in operable breast tumors and demonstrated that expression of α‐AR and β‐AR is associated with poor clinical outcome in BC.5 Particularly, numerous evidence confirm that α2‐AR plays an essential role in BC progression.