Figure 2D shows that the proportion of CD133+ cells was much higher in Panc-1-GR1 cells than in Panc-1 cells, suggesting the enrichment of pancreatic cancer stem cells. After treatment with 1 mM metformin, the proportion of CD133+ cells decreased significantly in Panc-1-GR1 cells. Figure 2E shows the sphere culture of Panc-1-GR1 cells. This evidence concerns the gene PROM1 and familial pancreatic carcinoma.