Recently, varied metal complexes, e.g., gold(I) complexes, have been found to be highly potent in suppressing the growth of cancer cells including drug-resistant cancer cells overexpressing ABC transporters or with other MDR mechanisms (Marmol et al., 2020; Abyar and Tabrizi, 2019; Chrysouli et al., 2018). Here, ABCG2 is linked to cancer.