ABCG2 and cancer: In the discovery and development of RuZ, Li et al. [3] provided insights from multiple perspectives: analyzing the physical properties and chemical molecular structure of RuZ, determining the cytotoxicity of RuZ in 35 cancer cell lines (including MDR cell lines), determining the cellular uptake mechanism of RuZ, calculating the interaction between RuZ and the ABCG2 and ABCB1 transporters (which can mediate MDR) and determining the mechanisms by which RuZ decreases cancer cell viability.