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 t test and χ2 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.