CELL-ADHESION MOLECULES IN HUMAN MENINGIOMAS - CORRELATION WITH CLINICAL AND MORPHOLOGICAL DATA

Integrins form a family of cell adhesion molecules. CD44 glycoproteins are found in a wide variety of isoforms; the most common, CD44s (stan dard) is widely distributed, and functions as an adhesion molecule. In this study, we have investigated immunohistochemically the distributi on of some VLA integrins (alpha 2, alpha 5 and alpha 6 chains of beta 1 integrins) and CD44s in 44 meningioma specimens and normal arachnoid villi. Meningiomas were of meningothelial (16), transitional (13) and fibroblastic (15) subtypes. There were 13 grade I, 19 grade II and 12 grade III (27%). Immunoprecipitates were quantified by image analysis and correlated with clinical (age, sex, location) and morphological d ata (histological subtypes and grades). VLA alpha 5 chain was expresse d by normal arachnoid villi (mainly cap cells) and by 42 out of 44 men ingioma specimens. Expression was lower in fibroblastic meningiomas (P =0.02). VLA alpha 2 and alpha 6 chains were not observed in normal ara chnoid villi. VLA alpha 2 was expressed by 15 meningiomas, VLA alpha 6 by 10. Interestingly, meningiomas expressing either VLA alpha 2 or al pha 6 were usually of grade III (P less than or equal to 0.05). CD44s was found on various parts of arachnoid villi and in all meningiomas a lthough expression was higher in meningothelial and transitional than in fibroblastic (P less than or equal to 0.001). These results show th at VLA alpha 5 and CD44s are widely expressed by arachnoid villi and m eningiomas. In contrast to VLA alpha 2 and VLA alpha 6. It was noted t hat high grade meningiomas (III) express VLA alpha 2 and alpha 6 sugge sting that changes in integrin pattern expression are a feature of the se meningiomas. Moreover, strong CD44s expression characterizes mening othelial and transitional meningiomas. Previous studies have shown tha t high NCAM expression is a feature of fibroblastic meningiomas wherea s meningothelial and transitional meningiomas expressed mainly E-Cadhe rin, and that polysialylated NCAM expression was restricted to high gr ade meningiomas. Taken together these features suggest that each cell adhesion molecule has a characteristic pattern of expression according to meningioma subtype and grade, No correlation was seen between inte grins and CD44s expression and clinical data.