Galectin-3: a biologic marker and diagnostic aid for chordoma.

Galectin-3 is a beta-galactoside binding protein. Its expression is quantitatively and qualitatively altered during self-proliferation, malignant transformation, and tumor progression. Galectin-3 is a lectin-related molecule. Lectins are proteins that bind specific carbohydrate structures. Although their precise biologic function is unclear, the general idea is that these molecules operate in modulating cell-to-cell and cell-to-matrix interactions. Galectins have been implicated in cell growth and differentiation and seem to play a role in malignant transformation and metastasis. Galectin-3 is expressed in primitive notochord. The purpose of the current investigation was to identify an immunohistochemical marker to help distinguish the pathologically overlapping entities of chordoma from myxoid low-grade chondrosarcoma. Twelve of 16 (75%) chordomas stained positive for Galectin-3 whereas only one of 12 low-grade myxoid chondrosarcomas stained positive. Galectin-3 chordoma staining is 75% sensitive and 92% specific.