Expression of the endogenous galactose‐binding protein galectin‐3 correlates with the malignant potential of tumors in the central nervous system

BACKGROUND The 31‐kilodalton β‐galactoside‐binding protein galectin‐3 has been associated with cellular transformation and metastasis. Because neural tissues contain large amounts of glycoconjugates, and endogenous carbohydrate‐binding proteins have been described in the human brain, the authors examined the expression of galectin‐3 in human brain tumors and metastases to the central nervous system. METHODS Brain tumors were categorized by the World Health Organization system and galectin‐3 expression by immunoperoxidase staining using a quantitative staining score. RESULTS Glioblastomas (Grade 4 astrocytomas) all stained strongly for galectin‐3, whereas low grade astrocytomas (Grade 2) did not express the endogenous lectin. Anaplastic astrocytomas (Grade 3) exhibited intermediate expression. The staining score was significantly associated with tumor grade (P < 0.001). Normal brain tissue and benign tumors did not express galectin‐3, whereas metastases to the brain were all positive for galectin‐3 expression. Metastases expressed significantly more galectin‐3 than the primary tumors from which they were derived (P = 0.003). CONCLUSIONS Galectin‐3 expression correlates with the malignant potential of tumors in the central nervous system. Cancer 1997; 80:776‐87. © 1997 American Cancer Society. Expression of the endogenous β‐galactoside‐binding protein galectin‐3 is significantly associated with the grade of malignancy of primary human brain tumors, and is also associated with metastases to the central nervous system.