ABSTRACT
<p><b>OBJECTIVE</b>To evaluate the expression of PTEN, MMP-2 and MMP-9 in thymomas and their correlation with clinical significance.</p><p><b>METHODS</b>Immunohistochemical S-P assay was used to detect the expression of PTEN, MMP-2 and MMP-9 in 45 thymomas and 16 non-neoplastic thymuses.</p><p><b>RESULTS</b>The positive rate of PTEN, MMP-2 and MMP-9 expression in 45 thymomas were 53.5%, 48.9% and 62.2%, respectively. There were significant differences between non-neoplastic thymus and thymomas (P < 0.05). The expression of PTEN, MMP-2 correlated with histological type (P < 0.05) and different clinical stage of the thymoma (P < 0.01). The expression of MMP-9 was not correlated with histological type and different clinical stages of thymoma (P > 0.05).</p><p><b>CONCLUSION</b>PTEN, MMP-2 and MMP-9 may play an important role in the occurrence and development of thymoma. The expression of PTEN and MMP-2 correlates with the malignance and the aggression of thymoma.</p>