Immunohistochemical expression of matrix metalloproteinase-9 in urothelial carcinoma of urinary bladder

Context
Bladder urothelial carcinoma is one of the most common cancers in both men and women worldwide. Matrix metalloproteinases (MMPs) are a family of endopeptidases capable of degrading essentially all extracellular matrix components. MMP-9 has multiple substrates; however, collagen type IV is the most crucial substrate. The proteolytic activity of MMP-9 not only promotes invasion and metastasis but also releases matrix-bound growth factors and other signaling molecules, participating in growth, angiogenesis, and inflammatory responses.
Aims
To evaluate the expression of MMP-9 in urothelial carcinoma of the bladder immunohistochemically, to correlate the expression with stromal invasion, tumor grade, and histological type, and to test for the usefulness of MMP-9 as ancillary test to distinguish different histological types and tumor grades
Settings and design
A retrospective study included the collection of 37 formalin-fixed, paraffin-embedded tissue blocks. Overall, 32 blocks/cases represent urothelial carcinoma of urinary bladder and five blocks/cases of reactive (inflammatory) conditions.
Patients and methods
Two sections from each case were stained with hematoxylin and eosin and immunohistochemically with MMP-9 antibodies, using rabbit monoclonal anti-human MMP-9 as a primary antibody.
Statistical analysis
It was performed with statistical package for the social sciences (SPSS Inc., Version 18.0, Chicago) and Excel 2007 program. Data analysis was done using test and test.
Results
Eighteen (56.25%) cases of the 32 total cases of urothelial carcinoma included in this study show a negative immunohistochemical expression for MMP-9 and 14 (43.75%) cases were positive for MMP-9. There was no statistical significant correlation between MMP-9 expression and tumor stage, grade, and histological type.
Conclusion
No statistical significance was found between MMP-9 immunohistochemical expression and the studied prognostic parameters: histological type, grade, and stage.