Lopez et al. characterized a self-renewing subpopulation of CSC among four cancer-derived cell lines, HeLa, SiHa, Ca Ski, and C-4 I, and found that these express the CSC markers characteristic of the FRS including CD44, ITGB1 (CD29), PSCA, NT5E (CD73), ENG (CD105), MYC (c-Myc), PCGF4 (BMI-1), and ABCG2. Other epithelial CSC markers found included ITGB6, ALCAM (CD166), and MET (c-Met) [32]. Here, BMI1 is linked to cancer.