Differentiation between high- and low-grade astrocytoma using a human recombinant antibody to the extra domain-B of fibronectin.
Different fibronectin (FN) isoforms are generated by the alternative splicing of the primary FN transcript. We previously demonstrated that the isoform containing the extra domain B sequence of fibronectin (B-FN), a complete type-III-homology repeat, is a marker of angiogenesis that accumulates around neovasculature only during angiogenic processes. We produced a single-chain human recombinant antibody (scFv), L19, which reacts specifically with B-FN and selectively targets tumor vasculature in vivo. We used this scFv and an antibody against a pan-endothelial marker (Factor VIII) in a double-staining procedure on specimens of low- and high-grade astrocytomas to determine the percentage of B-FN-positive vessels, (denominating the resulting value angiogenic index [AI]). Compared to vascular density and proliferative activity (evaluated using antibodies to Factor VIII and Ki67, respectively), AI correlated better with tumor grade (1.6 +/- 2.6% and 92.0 +/- 8.7% of B-FN-positive vessels in low- and high-grade astrocytomas, respectively) and was a more precise diagnostic tool than either of the two conventional methods. In fact, discriminating analysis using these three parameters showed that only AI accurately classified 100% of the cases studied, compared to 64% and 89% correctly diagnosed by vascular density and of proliferating cells, respectively.
Castellani
Patrizia
P
Laboratory of Cell Biology, Istituto Nazionale per la Ricerca sul Cancro, Genoa, Italy.
Borsi
Laura
L
Carnemolla
Barbara
B
Birò
Attila
A
Dorcaratto
Alessandra
A
Viale
Giuseppe L
GL
Neri
Dario
D
Zardi
Luciano
L
D000906:Antibodies / Q000235:genetics / Q000276:immunology*; D001254:Astrocytoma / Q000097:blood / Q000145:classification* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000032:analysis / Q000737:chemistry / Q000276:immunology*; D005169:Factor VIII / Q000032:analysis / Q000276:immunology; D005353:Fibronectins / Q000032:analysis / Q000737:chemistry / Q000276:immunology*; D006801:Humans; D007150:Immunohistochemistry; D019394:Ki-67 Antigen / Q000032:analysis / Q000276:immunology; D009389:Neovascularization, Pathologic; D017434:Protein Structure, Tertiary; D011994:Recombinant Proteins / Q000276:immunology
D000906:Antibodies; D014408:Biomarkers, Tumor; D005353:Fibronectins; D019394:Ki-67 Antigen; D011994:Recombinant Proteins; D005169:Factor VIII