Object: Matrix metalloproteinase (MMP) 2 and 9 are important for tissue breakdown in the process of tumor invasion. The aim of this study is to evaluate the relationship between the expression of MMP-2, MMP-9, MIB-1 LI and cavernous sinus invasion in pituitary adenomas.
Methods: Tissue samples from 54 patients with pituitary adenomas were studied. Expression of MMP-2, MMP-9, and MIB-1 labeling index (LI) were evaluated by immunohistochemical method. In sixteen cases, the expression of MMP-2 and MMP-9 mRNA was also examined by RT-PCR assay.
Results: Thirty-four patients were women and 20 were men, with a mean age of 49.9 years old (range 18-76 years). There were 12 cases with cavernous sinus invasion, and 42 were noninvasive cases. MMP-2 and MMP-9 score of invasive case (3.9 +/- 0.5,4.1 +/- 0.4) were significantly higher than those (2.3 +/- 0.2; p < 0.01; 2.6 +/- 0.2; p < 0.01) without invasion. The MIB-1 LI of this study presented no significantly difference between the invasive and noninvasive pituitary adenomas. The percentage of MMP-2 mRNA/beta-actin mRNA and MMP-9 mRNA/beta-actin mRNA were also observed significantly higher in invasive pituitary adenomas (68.2 +/- 15.3%; 59.7 +/- 12.5%) than noninvasive pituitary adenomas (21.8 +/- 8.2%, p < 0.05; 33.3 +/- 5.4%, p < 0.05).
Conclusions: Our study suggests that the expression of MMP-2 and MMP-9 may have a value to assess the invasive pituitary adenomas, and proliferation and invasion of pituitary adenomas may present a different mechanism.