Etique et al. have found that A2aR was overexpressed in the hormone-dependent breast cancer cell line MCF-7 by RT-PCR analyses and immunocytochemistry experiments, and further research confirmed that activation of A2aR by the selective agonist CGS21680 was able to stimulate proliferation of MCF-7 breast cancer cells [34]. Here, ADORA2A is linked to breast cancer.