Galectin-3

Galectin-3 is a 30 kD protein, a member of the b-galactosidase-binding lectin family. Its function is uncertain, but it has been implicated in processes including cell growth, adhesion, inflammation, mRNA processing² and apoptosis.

Immunohistochemical expression

It is predominantly expressed in the nucleus², but also in the cytoplasm and cell membrane of epithelial and immune cells.

• neutrophil polymorphs

• vascular endothelium

• Over-expression is related to malignant transformation and metastasis in carcinomas of the breast, colon, tongue and liver².

• Over-expression has been reported in thyroid follicular carcinomas but absent in follicular adenomas.

Diagnostic utility

• Differentiation between follicular adenoma, follicular carcinoma and papillary carcinoma of the thyroid, in conjunction with cytokeratin 19. Galectin-3 shows the most intense staining in the advancing tongues of minimally invasive follicular carcinoma¹ and may be helpful in differentiating a follicular adenoma from a minimally invasive carcinoma. Not all authors agree that it is reliable in differentiating benign from malignant thyroid lesions².

References

¹Beesley, M.F. and McLaren, K.M. Cytokeratin 19 and galectin-3 immunohistochemistry in the differential diagnosis of solitary thyroid nodules. Histopathology 2002;41:236-43.

²Mehrotra, P., A. Okpokam, et al. (2004). "Galectin-3 does not reliably distinguish benign from malignant thyroid neoplasms." Histopathology 45(5): 493-500.

This page last revised 12.1.2005.

©SMUHT/PW Bishop