In the present study, we succeeded in establishing a cancer stem cell line from clear cell carcinoma of the ovary (CCC), which has the worst prognosis among epithelial ovarian cancers [4] and show that CD133 interacts with plakoglobin, controls desmoglein-2 protein levels and is required for cell-cell adhesion and tumorigenicity of CCC stem cells. The gene discussed is PROM1; the disease is cancer.