BMI1 and gastric cancer: Our results showed that compared to GES-1, a normal immortal human gastric mucosal epithelial cell line, the majority of gastric cancer cell lines expressed high BMI1 (5 out of 8 at the RNA and protein levels) and low Mel-18 (4 out of 8 at the RNA level and 5 out of 8 at the protein level) (Fig 1A, 1B).