Abstract
Purpose: :
Maspin is a mammary serine protease inhibitor with tumor suppressive activities observed in breast and prostate cancers. Maspin expression was recently correlated with decreased angiogenesis and with thin cutaneous melanomas. Moreover, loss of maspin expression was correlated with a more aggressive behaviour in these tumors. The aim of this study was to identify the role of maspin in uveal melanoma (UM) and to correlate expression with prognostic factors and disease outcome.
Methods: :
Sixteen formalin-fixed, paraffin-embedded UM specimens were retrieved from the Henry C. Witelson Ocular Pathology Laboratory Registry and immunostained for maspin expression. The expression was classified according to intensity (0-3) and percentage (0-3) of the positive tumor cells. Intensity was graded as negative (0), weak (1), moderate (2) or strong (3). Percentage was graded as negative (0), < 25% (1), 25-50% (2) or ≥ 50% (3) of positive UM cells. A final immunohistochemical score based on intensity and percentage of cells was established as negative (0), weak (2), moderate (3-4) or strong (5-6). Maspin expression was compared independently to tumor size, cell type, tumor location, and occurrence of liver metastasis using Student’s t-test and a p-value of <0.05 was considered statistically significant.
Results: :
Immunohistochemistry revealed maspin expression in 12 of the 16 UM cases. There was a significant inverse relationship between maspin expression and largest tumor dimension (p = 0.0064). Tumors above 15 mm (n=6) revealed weak or negative maspin expression. There was no correlation between maspin expression and tumor location (p = 0.15), cell type (p = 0.25), or occurrence of metastasis (p = 0.67).
Conclusions: :
To the best of our knowledge this is the first time that maspin expression has been evaluated in Uveal Melanoma. Downregulation of maspin may contribute to tumor growth and progression in Uveal Melanoma, as seen in cutaneous melanoma. Further studies are needed to establish the functional role of maspin in proliferation of Uveal Melanoma cells.
Keywords: tumors • melanoma • gene/expression