Galectins are a family of carbohydrate binding proteins that have been shown to have diverse biological activities. Recent evidence points to a role for galectins in tumorigenesis through multiple mechanisms including angiogenesis, metastasis, and immune system evasion. To date there is limited data available for galectins and their role in canine cancers. The purpose of this study was to examine the expression levels and the patterns of expression of galectin-1, 3, and 7 in canine hemangiosarcoma (HSA).
Expression of galectin-1, 3, and 7 using were elevated in normal canine spleen and splenic hemangiosarcoma using western blot analysis and immunohistochemistry.
Semi-quantitative analysis of the western blots did not indicate significant expressional differences for galectin 1 or 3 in HSA and normal spleen. Expression of galectin 7 was variable but without significant pattern between tumors and normal spleen. Immunohistochemistry indicated no staining of tumor cells for galectin-1 and 7, whereas 15-20% of tumor and normal cells had weak cytoplasmic staining for galectin-3. There was no difference between individual tumors in galectin-3 staining. Inflammatory cells, particularly histiocytic cells, and reactive fibroblasts within in normal tissues and tumors had strong cytoplasmic signals for galectin-3. The stroma of tumor and normal tissues had weakly positive staining for Galectin-1 without appreciable difference between individual tumors or normal tissue. Our data do not support a role for these galectins in canine hemangiosarcoma tumorigenesis, which is in contrast to our observations in canine epithelial malignancies.