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. It is best used in a panel with other markers such as CK19, HBME-1 and CITED1. 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