To identify the role of LGR5 in ovarian cancer, we first browsed the Oncomine (http://www.oncomine.org) database of cancer transcriptome profiles and found that the gene expression levels of LGR5 were significantly higher in tumor compared with related normal tissues (Fig. 1A) and closely correlated with tumor grade (Fig. 1B and C). This evidence concerns the gene LGR5 and ovarian cancer.