PTEN, one of the most frequently mutated and deleted tumour suppressor in the multitude of tumour types51, has frequently been reported downregulated in NPC52, 53 while the mutation or deletion of PTEN has rarely been detected in oral squamous cell carcinoma54, suggesting other mechanisms in NPC are likely responsible for the downregulation of PTEN. This evidence concerns the gene PTEN and nasopharyngeal carcinoma.