Abstract: To detect the expression and mutation of tumor suppressor PTEN in nasopharyngeal carcinoma（NPC）， and to　investigate the relationship of the PTEN gene to pathogenesis and development of NPC． MethodsExpression levels of PTEN in 52 cases of NPC were determined by an immunohistochemistry method， and polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP), while silver staining and DNA sequencing were used to detect the mutation in exon 5 and 8 of the PTEN gene in NPC. ResultsDifferences of the PTEN expression were significant between NPC and nasopharyngitis (P＜0.05)． Expressions of PTEN were closely related to lymph node metastasis and clinical TNM stage(P＜0.05). None of 52 cases showed mutation in exon5 and 8 of the PTEN gene in NPC． ConclusionPTEN may have some effects on the pathogenesis and development of NPC, and mutation in exon 5 and 8 of PTEN may not play a main role in the genesis and development of NPC.

Key words: Genes, PTEN, Nasopharyngeal neoplasms, Point mutation, Immunohistochemistry