EXPRESSION OF LAMININ-1 AND LAMININ-2 IN BRAIN-TUMOR VESSELS - AN IMMUNOHISTOCHEMICAL STUDY

Components of the blood-brain barrier (BBB) include capillary endothel ial cells, the vessel basement membrane (BM) and glial cell interface. While endothelial cell peculiarities are well known and thoroughly st udied, BM morphology and functional properties are not. Vessel BM thro ughout the body is composed of laminin 1, the most common variant of l aminin, which is made up of alpha 1, beta 1, and gamma 1 laminin chain s, while cerebral vessel BM has been reported to also express the alph a 2 chain. In the present study, we show that the BM of newly formed v essels in brain tumors presents the same immunohistochemical structure as normal brain vessel BM, expressing alpha 1, alpha 2, beta 1, and g amma 1 laminin chains. The function of this particular vessel structur e in the central nervous system is not yet completely understood; howe ver, we hypothesize that vessel BM could play a role in impeding the e xtraneural spreading of brain tumors.