Monoclonal antibody BrE-3 participation in a multivariate prognostic model for infiltrating ductal carcinoma of the breast.

Monoclonal antibody (MoAb) BrE-3, an anti-human milk fat globule (HMFG) MoAb, is used here as a novel prognostic indicator for survival and relapse time in patients with infiltrating ductal carcinoma of the breast. A scoring system (4-Score method) was developed to this effect that measured, in a statistically reliable fashion, the level of expression of the epitope for MoAb BrE-3 in the cytoplasm and membranes of breast carcinoma cells in paraffin-embedded sections. In univariate analysis, data obtained by the 4-Score Method as well as data from traditional prognostic indicators (tumor size, axillary node status, and grade of differentiation) were found to be associated with patient survival and relapse. In multivariate analysis, using a Cox proportional hazards regression model, levels of expression of BrE-3 epitope plus tumor size and axillary node status were weighted and combined in an Individual Linear Composite Prognostic Score (ILCPS) that had a high level of association with survival and relapse time in this sample model of patients with infiltrating ductal carcinoma of the breast. This level of association was found to be higher than the level of association for any other combination of traditional or 4-Score method variables. The level of expression of BrE-3 significantly adds to the prognostic capacity of traditional prognostic markers for infiltrating ductal carcinoma of the breast.