Objective      To investigate the expression and clinical significance of phosphatase and tensin homolog deleted on chromosome ten (PTEN) in oral squamous cell carcinoma (OSCC). Methods      Tissue samples from 30 cases of OSCC and from the matched paracarcinoma regions (from 2 cm of the tumors) were collected. Western blot analysis and qRT-PCR were used to detect the expression of PTEN at protein and mRNA levels. And immunohistochemical assay was employed to observed the location and distribution of the protein. The obtained results were analyzed for their relationship with OSCC clinical pathology. Results      ① PTEN protein was positively expressed in the paracancerous tissues

and mainly located in the cytoplasm within the brown or brown stain. But it was not detected in the most OSCC tissues. ② The protein and mRNA levels of PTEN were significantly lower in the OSCC tissues than in the paracancerous regions (P0.05). ③ There were no significant differences in the protein and mRNA levels of PTEN from different positions of the tumors and among the patients from different age and sex (P0.05). ④The expression of PTEN were higher in well-differentiated tumors than moderately differentiated and undifferentiated tissues (P0.05). ⑤The patients without lymph metastasis exhibited significantly increased expression of PTEN compared with those with lymph metastasis (P0.05). ⑥ PTEN expression levels were significantly higher in the patients of stage Ⅰ＋Ⅱ than those of stage Ⅲ＋Ⅳ (P0.05). Conclusion      PTEN is abnormally expressed in the OSCC tissues to some extent

and it may be a key factor in tumorigenesis

invasion and migration of OSCC.