Expression of beta 1 and beta 4 integrins in normal arachnoid membrane andmeningiomas

BACKGROUND. The aim of this work was to study the expression of alpha, beta 1, and beta 4 integrin subunits in meningiomas. METHODS. Seventeen atypical or anaplastic meningiomas were retrieved from t he files of Hopital de Bellevue, Saint-Etienne, France. They were compared with 17 benign meningiomas consecutively examined in 1997 and 6 schwannomas . The tumors were classified according to standard histologic criteria. Fro zen sections were immunostained for alpha 1, alpha 2, alpha 3, alpha 4, alp ha 5, alpha 6, beta 1, and beta 4 integrin subunits; collagen; laminin and fibronectin; cytokeratin; vimentin; neural cell adhesion molecule (NCAM); a nd MIB-1. RESULTS. The study included 7 fibrous meningiomas, 6 transitional meningiom as, 19 syncytial meningiomas, and 2 secretory meningiomas. The expression o f alpha 1, alpha 3, alpha 5, alpha 6, and beta 1 was constant. The expressi on of alpha 1 was higher in fibrous meningiomas than in syncytial meningiom as. Only in transitional, syncytial, and secretory meningiomas was the expr ession of alpha 2 detected. The expression of alpha 2 and beta 4 was associ ated with the expression of cytokeratin in the glandular structures of secr etory meningiomas, whereas it was associated with NCAM expression in the wh orls of meningothelial meningiomas. The expression of integrin receptors by tumor cells was strongly correlated with that of their respective ligands in the extracellular matrix. In invasive meningiomas, the expression of alp ha 3 and alpha 6 by tumor cells was significantly lower. The higher the MIB -1 proliferation index, the lower the expression of alpha 3. The 6 schwanno mas expressed only alpha 2, alpha 3, alpha 6, beta 1, and beta 4 integrins. CONCLUSIONS. Each histologic subtype of meningioma has a specific spectrum of integrin expression. The study of alpha 3 and alpha 6 may have prognosti c value in the assessment of meningiomas. The study of the integrin profile is valuable for the differential diagnosis of fibrous meningiomas and schw annomas. (C) 1999 American Cancer Society.