Abstract
Abstract: :
Purpose: To determine the quantitative expression of matrix metalloproteinase–9 (MMP–9) in intraocular primary malignant melanoma. To examine a set of clinical and histomorphometrical variables in search for a reproducible parameter that can serve as a diagnostic and prognostic criteria. Methods: A total of 92 cases of uveal malignant melanoma were selected from the Armed Forces Institute of Pathology files. The tumors were classified according to clinico–pathological findings, and two morphometric variables, cell type (NTC) and the mean size of the longest nucleoli (MLN) were utilized along with patient survival outcome. Immunohistochemical studies on the same specimens were performed in intraocular primary malignant melanomas and appropriate positive and negative controls, formalin fixed and paraffin embedded. Bleached tissue sections were probed with antibody against human MMP–9 (R & D systems Inc, Chemicon International Inc.) and binding was visualized as red pigment using a secondary antibody and employing an Avidin Biotin complex kit (Vectastain Elite ABC kit, Vector Laboratories). Using a Q–imaging Micropublisher 5.0 color digital camera, five representative pictures were taken per each tumor. A computer based system (Olympus Micro Suite, Olympus America, Inc. NY) was used to quantitatively analyze the representative pictures. The degree of staining was expressed as intensity and area percentage of whole sections. This experiment was designed as a double blind study. Results: Univariate analysis using the Cox proportional–hazards model showed a strong correlation between death from metastatic ocular malignant melanoma and the percentage of MMP–9 staining, as well as between survival and the other evaluated morphometric factors – NTC and MLN. These results suggest that matrix metalloproteinase–9 expression might be involved or associated in the progression of the disease. Conclusions: Image analysis with immunohistochemical studies is feasible and yields data that improves diagnostic and prognostic accuracy. In this study, we have identified a distinct MMP–9 immunostaining pattern in different ocular melanomas that may be used to predict the aggressiveness of tumor growth.
Keywords: pathology: human • melanoma • immunohistochemistry