title: The expression of rho proteins decreases with human brain tumor progression: potential tumor markers.
abstract: Astrocytic tumors are the most common human brain tumors. Establishment of tumor grade is a key determinant both in the choice of a therapeutic approach and in the prognosis. The diagnosis of astrocytic tumors is currently determined following histopathological analysis. The identification of molecular markers would offer a complementary tool for characterizing tumors with respect to their clinical behavior. In this study we determined the expression levels of 3 small GTP binding proteins (RhoA, RhoB and Rac1), of their inhibitor RhoGDI and of caveolin-1 in 24 human astrocytic tumors of grades I to IV. Our results demonstrated that the expression of RhoA and RhoB decreased significantly in all brain tumors studied and was inversely related with tumor of grade II to IV malignancy. The amount of caveolin-1 immunodetected was not significantly different from normal brain samples while the Rac1 expression level was diminished in astrocytic tumors of grades III and IV. Our finding that RhoA and RhoB expression levels are correlated to tumor malignancy suggests that they may serve as novel and efficient diagnostic markers for astrocytic brain tumors of histological grade II to IV and complement currently applied histopathological analysis.
authors.affiliation: Laboratoire de Médecine Moléculaire, Hôpital Sainte-Justine-Université du Québec à Montréal, Canada.
authors.forename: Marie-Annick
authors.initials: MA
authors.lastname: Forget
authors.forename: Richard R
authors.initials: RR
authors.lastname: Desrosiers
authors.forename: MaestroRolandaF
authors.initials: M
authors.lastname: Del
authors.forename: Robert
authors.initials: R
authors.lastname: Moumdjian
authors.forename: Daniel
authors.initials: D
authors.lastname: Shedid
authors.forename: France
authors.initials: F
authors.lastname: Berthelet
authors.forename: Richard
authors.initials: R
authors.lastname: Béliveau
mesh_terms: D001254:Astrocytoma / Q000201:enzymology*; D014408:Biomarkers, Tumor / Q000096:biosynthesis* / Q000235:genetics; D001932:Brain Neoplasms / Q000201:enzymology* / Q000473:pathology; D051242:Caveolin 1; D022461:Caveolins / Q000032:analysis; D018450:Disease Progression; D004790:Enzyme Induction; D005909:Glioblastoma / Q000201:enzymology*; D020730:Guanine Nucleotide Dissociation Inhibitors / Q000032:analysis; D006801:Humans; D009363:Neoplasm Proteins / Q000032:analysis*; D020830:rac1 GTP-Binding Protein / Q000032:analysis; D020741:rho GTP-Binding Proteins / Q000032:analysis*; D062948:rho Guanine Nucleotide Dissociation Inhibitor alpha; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020742:rhoA GTP-Binding Protein / Q000032:analysis; D020743:rhoB GTP-Binding Protein / Q000032:analysis
chemical_list: C569638:ARHGDIA protein, human; D014408:Biomarkers, Tumor; C495540:CAV1 protein, human; D051242:Caveolin 1; D022461:Caveolins; D020730:Guanine Nucleotide Dissociation Inhibitors; D009363:Neoplasm Proteins; D062948:rho Guanine Nucleotide Dissociation Inhibitor alpha; D062947:rho-Specific Guanine Nucleotide Dissociation Inhibitors; D020830:rac1 GTP-Binding Protein; D020741:rho GTP-Binding Proteins; D020742:rhoA GTP-Binding Protein; D020743:rhoB GTP-Binding Protein