title: Increased expression of podoplanin in malignant astrocytic tumors as a novel molecular marker of malignant progression.
abstract: Podoplanin (aggrus) is a mucin-like transmembrane sialoglycoprotein that is expressed on lymphatic endothelial cells. Podoplanin is putatively involved in cancer cell migration, invasion, metastasis, and malignant progression and may be involved in platelet aggregation. Previously, we showed upregulated expression of podoplanin in central nervous system (CNS) germinomas, but not in non-germinomatous germ cell tumors, except for parts of immature teratomas in limited numbers. However, little information exists about its role in CNS astrocytic tumors. In this study, 188 astrocytic tumors (30 diffuse astrocytomas, 43 anaplastic astrocytomas, and 115 glioblastomas) were investigated using immunohistochemistry with an anti-podoplanin antibody, YM-1. In 11 of 43 anaplastic astrocytomas (25.6%) and in 54 of 115 glioblastomas (47.0%), podoplanin was expressed on the surface of anaplastic astrocytoma cells and glioblastoma cells, especially around necrotic areas and proliferating endothelial cells. However, the surrounding brain parenchyma was not stained by YM-1. On the other hand, podoplanin expression was not observed in diffuse astrocytoma (0/30: 0%). Furthermore, we investigated the expression of podoplanin using quantitative real-time PCR and Western blot analysis in 54 frozen astrocytic tumors (6 diffuse astrocytomas, 14 anaplastic astrocytomas, and 34 glioblastomas). Podoplanin mRNA and protein expression were markedly higher in glioblastomas than in anaplastic astrocytomas. These data suggest that podoplanin expression might be associated with malignancy of astrocytic tumors.
authors.affiliation: Department of Neurosurgery, Saitama Medical School, Saitama, 350-0495, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Mishima
authors.forename: Yukinari
authors.initials: Y
authors.lastname: Kato
authors.forename: Mika Kato
authors.initials: MK
authors.lastname: Kaneko
authors.forename: Ryo
authors.initials: R
authors.lastname: Nishikawa
authors.forename: Takanori
authors.initials: T
authors.lastname: Hirose
authors.forename: Masao
authors.initials: M
authors.lastname: Matsutani
mesh_terms: D001254:Astrocytoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D016543:Central Nervous System Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D018450:Disease Progression; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D000098853:Podoplanin
chemical_list: D014408:Biomarkers, Tumor; D008562:Membrane Glycoproteins; D012333:RNA, Messenger; C117468:PDPN protein, human; D000098853:Podoplanin