CD9 expression in solid non-neuroepithelial tumors and infiltrative astrocytic tumors.
The tetraspan membrane protein CD9 is normally expressed in the mature myelin sheath and is believed to suppress the metastatic potential of certain human tumors. In this study we identified CD9 in a variety of brain tumors by immunohistochemical (IHC) and immunoblotting analyses. We examined 96 tumor samples and three glioma cell lines in addition to a murine brain tumor model of transplanted glioma cells in CD9-deficient mice and control mice. CD9 was expressed not only in solid non-neuroepithelial tumors but also in infiltrative malignant neuroepithelial tumors. Among the neuroepithelial tumors, high-grade astrocytic tumors, including glioblastomas and anaplastic astrocytomas, showed higher immunoreactivity than low-grade cerebral astrocytomas. Thus, CD9 expression in astrocytic tumors correlated with their malignancy. In the murine brain tumor model, transplanted glioma cells were shown to grow and spread through myelinated areas irrespective of the presence or absence of CD9 expression in the recipient's brain. These results indicate that the CD9 expression of astrocytic tumors plays a significant role in the malignancy independent of CD9 expression in the surrounding tissue. This might be explained by the observation that the CD9 molecule is associated with a mitogenic factor, membrane-anchored heparin-binding epidermal growth factor, which is known to be upregulated in malignant gliomas.
Department of Neuropathology, Neurological Institute, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan. kawasm@neurosurgery.ufl.edu
Masatou
M
Kawashima
Katsumi
K
Doh-ura
Eisuke
E
Mekada
Masashi
M
Fukui
Toru
T
Iwaki
D000293:Adolescent; D000368:Aged; D000818:Animals; D015703:Antigens, CD / Q000378:metabolism*; D001254:Astrocytoma / Q000378:metabolism; D001932:Brain Neoplasms / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D002648:Child; D002675:Child, Preschool; D005260:Female; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007150:Immunohistochemistry; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D008562:Membrane Glycoproteins; D051379:Mice; D008875:Middle Aged; D018302:Neoplasms, Neuroepithelial / Q000378:metabolism; D013116:Spinal Cord / Q000378:metabolism; D060245:Tetraspanin 29; D014407:Tumor Cells, Cultured
D015703:Antigens, CD; C554869:CD9 protein, human; C554870:Cd9 protein, mouse; D008562:Membrane Glycoproteins; D060245:Tetraspanin 29