Additionally, Peng et al. utilized tamoxifenas an ER-targeting unit and qualitatively demonstrated increased cellularuptake and photodynamic therapeutic efficacy in ER+ cancer cells comparedto its tamoxifen-free counterpart. Thesestudies suggest that incorporating ER-targeting moieties into Ru­(II)polypyridyl complexes could be a promising approach to improving selectivityfor ER+ cancer cells. This evidence concerns the gene ESR1 and cancer.