As the expression of Bmi-1 is negatively regulated by Pten, which acts as a tumor suppressor gene [54], increased expression of Bmi-1 may correlate with repression of Pten expression and induction of epithelial-mesenchymal transition, as well as increased motility and invasiveness of human nasopharyngeal epithelial cells [54]. Here, PTEN is linked to neoplasm.