Tumor sphere formation assay showed that CD133+ cells with RAI2 re-expressed formed fewer and smaller spheres than the control group (P=0.0285 in LoVo, P=0.0048 in HCT116) (Figure 5A, right panel), suggesting that RAI2 inhibited the self-renewal ability of CRC cells. The gene discussed is PROM1; the disease is neoplasm.