Furthermore, we demonstrated that silencing of Sp1 inhibited cell proliferation, clonogenicity, anchorage-independent growth and the stem-cell like phenotype of NPC cells through inducing the expression of p27 and p21, and through impairing the expressions of SCTFs, including Bmi1, c-Myc, KLF4, NANOG and OCT4 in NPC cells. This evidence concerns the gene KLF4 and nasopharyngeal carcinoma.