Sphere formation assay, commonly used to identify cancer stem cells, was carried out and showed that the size and number of spheres were less and smaller in PDLSCs with knockdown of CUL4B, whereas were more and bigger in CUL4B overexpressed PDLSCs when comparing to the corresponding control group (Figures 2C,D and Supplementary Figure S2J). The gene discussed is CUL4B; the disease is cancer.