Abstract
Abstract: :
Purpose: To determine the quantitative expression of matrix metalloproteinases–9 (MMP–9) and 14 (MMP–14) in intraocular primary malignant melanoma. To evaluate a set of clinical and histomorphometrical variables in search of a reproducible prognostic parameter which can predict patient outcome. Methods: 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. Two morphometric variables, cell type (NTC) and the mean size of the longest nucleoli (MLN) were utilized along with patient survival outcome. Immunohistochemistry was performed on paraffin embedded melanoma tissues and bleached tissue sections were probed with antibodies against human MMP–9 and human MMP–14 (R & D systems Inc, Chemicon International Inc.). The binding was visualized as a red pigment using the secondary antibody and the 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 tumor which were analyzed by a computer–based system (Olympus Micro Suite, Olympus America, Inc. NY). The degree of staining was expressed as intensity and average of area percentage (ave) of whole sections. This experiment was designed as a double blind study. Results: Multivariate 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, MLN and NTC. For each one unit increase above the ave of MMP–9 staining, the hazard of death goes up by an estimated 25.7% and for each one unit increase in MLN, the hazard of death goes up by an estimated 69.6%, controlling for the other variables. For each one unit increase above the ave of MMP–14 staining, the hazard of death goes up by an estimated 6.5%. There was no correlation with the intensity of staining. Conclusions: In this study, we have quantified the distinct MMP–9 and MMP–14 immunostaining patterns in ocular melanomas using a computer based image analysis. Although MLN still remains the most significant predictor of mortality, MMP–9 staining percentage coupled with MLN, add significantly as outcome prognostic indicators, with higher values carrying an increased hazard of death. They can be collectively used as vital parameters in patient prognosis during enucleation and histopathological evaluation.
Keywords: pathology: human • melanoma • immunohistochemistry