Regarding the difficulty in the clinical applications of existing ABCG2 inhibitors, our recent study may open up further avenues, in which febuxostat—an approved agent for hyperuricemia globally used in clinical situations—was serendipitously identified as a strong ABCG2 inhibitor both in vitro and in vivo (Miyata et al., 2016). The gene discussed is ABCG2; the disease is hyperuricemia.