Laminin

This is an important component of basement membranes. It acts as a bridge between collagen type IV in the basement membrane and the glycosaminoglycans of the surrounding matrix. In soft tissues, complete basement membranes form around endothelial, smooth muscle and Schwann cells: antibodies against laminin and collagen IV are useful for the identification of these lineages.

Laminin 5 is a heterodimer of a3, b3 and c2 chains. Laminin 5 binds epithelial cells to the basement membrane through hemidesmosomes2.

• In the breast, myoepithelial cells express both b3 and c2 chains; luminal cells do not2.

Laminins 6 and 7 also express the a3 chain.

Diagnostic utility

• Laminin 5 may be useful in the diagnosis of metaplastic carcinoma of the breast.

References

1Diagnostic Immunohistochemistry edited by Professor D. J. Dabbs, page 70

2 Carpenter PM, Wang-Rodriguez J, Chan OT, et al. Laminin 5 expression in metaplastic breast carcinomas. Am J Surg Pathol 2008; 32:345-53

This page last revised 21.12.2001.

©SMUHT/PW Bishop