Introduction Galectin-1 (Gal-1) is a member of the galectin family of proteins, which are carbohydrate-binding proteins with an affinity for β-galactosides. Gal-1 is differentially expressed by various normal and pathological tissues and it performs polyvalent, wide-ranging biological activities. A Gal-1 expression or over-expression in tumors and/or in the tissue surrounding them must be considered as a sign of malignant tumor progression that is often related to tumor metastasis. Although Gal-1 also plays important roles for tumorigenesis and tumor progression, the expression of Gal-1 in melanocytic nevus, dysplastic nevus and malgant melanoma has not yet been investigated. We wanted to investigate and compare the expression of Gal-1 in melanocytic nevus, dysplastic nevus and malignant melanoma.
Methods The paraffin-embedded specimens of 9 cases of malignant melanoma (MM), 6 cases of dysplastic nevus (DN) and 6 cases of intradermal nevus (IN) were subjected to immunohistochemical staining for Gal-1.
Results The percentage of positive cells for Gal-1 in the MM was significantly higher than that of the DN and IN (P<0.01). The staining intensity of the positive cells for Gal-1 was the highest also in the MM. Meanwhile Gal-1 was more strongly expressed in highly atypical (more pleomorphic, more atypical mitoses) areas of the melanoma tissues. There was no significant difference between DN and IN for the expression of Gal-1.
Conclusion The present study suggests that Gal-1 is more strongly expressed in malignant melanoma than in melanocytic nevus and dysplastic nevus. Interestingly, Gal-1 was more strongly expressed in the highly atypical portions of the melanoma tissue. Gal-1 might well contribute to the tumorigenesis and malignancy of melanocytes.