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.