The research paper “Expression of potential cancer stem cell marker ABCG2 is associated with malignant behaviors of hepatocellular carcinoma” by G. Zhang et al. found that ABCG2 could probably function as a liver cancer stem cell marker because of its close relationship with tumorigenesis and also because it could promote cell proliferation, drug resistance, and metastasis. This evidence concerns the gene ABCG2 and hepatocellular carcinoma.