ABCG2 and gastric cancer: Yu et al. (2014) found that genistein markedly reduced the Gli1 level, which is considered a mediator of the SHH signaling pathway; such a mechanism involves specific CSC hallmarks of gastric cancer (GC) including CD44 expression, stem-cell-related genes (i.e., Oct-4, Bmi, Nestin, and adenosine triphosphate (ATP)-binding cassette efflux transporter G2(ABCG2)), spheroid formation, as well as migration and invasion propulsion [160].