Prognostic value of a breast cancer-associated glycoprotein detected by monoclonal antibody LU-BCRU-G7

The immunohistochemical reactivity of a second generation murine monoclonal antibody (LU-BCRU-G7), raised against a novel fucosylated glycoprotein of M r 230 000, has shown a significant association with prognosis of early stage carcinomas. Staining was observed in 72% of the 190 breast carcinomas tested. No relationship with steroid receptor status, stage or node status was found. An association with grade was observed ( χ 2 7.83, 2 degrees of freedom, P = 0.02) only when the negative cut-off level was raised from < 10% cells staining to < 25%. Antibody reactivity was always cytoplasmic. Immunoblotting shows the antibody is reactive with a component of M r 230 000 not detected by HMFG 2. A significant association was found between lack of reactivity and improved disease-free interval (0.005 > P > 0.001) and survival (0.02 > P > 0.01). Subdivision of cases on the basis of node status showed that staining could refine survival data. A decreased reactivity of LU-BCRU-G7 was observed after pretreatment with β-galactosidase but not a sialidase or β- N-acetylhexosaminodase indicating that non-reducing terminal galactose residues in β1–3 or β1–4 linkages may be involved in the antibody binding site. This approach has identified a useful and novel prognostic marker in early stage human breast carcinoma.