Expression of laminin 1 and 2 in brain tumor vessels. An immunohistochemical study.

: Components of the blood-brain barrier (BBB) include capillary endothelial cells, the vessel basement membrane (BM) and glial cell interface. While endothelial cell peculiarities are well known and thoroughly studied, BM morphology and functional properties are not. Vessel BM throughout the body is composed of laminin 1, the most common variant of laminin, which is made up of alpha 1, beta 1, and gamma 1 laminin chains, while cerebral vessel BM has been reported to also express the alpha 2 chain. In the present study, we show that the BM of newly formed vessels in brain tumors presents the same immunohistochemical structure as normal brain vessel BM, expressing alpha 1, alpha 2, beta 1, and gamma 1 laminin chains. The function of this particular vessel structure in the central nervous system is not yet completely understood; however, we hypothesize that vessel BM could play a role in impeding the extraneural spreading of brain tumors.