PTEN and nasopharyngeal carcinoma: Alterations of the expression of EBV-miR-BART1 demonstrated that it induces the migration and invasion of NPC cells in vitro and the tumour metastasis in vivo. The underlying molecular mechanisms by which BART1 causes tumour metastasis are revealed to directly target the major tumour suppressor, phosphatase and tensin homologue (PTEN) and consequently to activate PTEN-dependent pathways and induce epithelial–mesenchymal transition (EMT).