Also known as breast cancer-resistant protein (BCRP), clinical data have shown that the overexpression of ABCG2 contributes to resistance against various chemotherapeutic agents in patients with different types of cancer, including non-small cell lung cancer (Lemos et al., 2011), hepatocellular carcinoma (Chen et al., 2016), acute myeloid leukemia (Damiani et al., 2016), acute lymphoblastic leukemia (Suvannasankha et al., 2004), and other cancers types (Wang et al., 2017). The gene discussed is ABCG2; the disease is hepatocellular carcinoma.