BMI1 and neoplasm: Increased mRNA levels of Bmi-1 as well as OCT4, NANOG, NOTCH1, ALDH1, SOX2, and CD133 were also found in spontaneously formed hybrid cells derived from non-small cell lung cancer cells and bone-marrow-derived mesenchymal stem cells, which also possessed an increased pneumosphere-forming capacity and tumor-forming ability [20].