ErbB2 assay in breast cancer: Possibly improved clinical information using a quantitative method

ErbB2/neu protein (p185) expression was evaluated by ELISA in IIS breast cancer specimens. Distribution was subdivided in guartiles and showed a distinct behaviour in comparison with both clinico-biological parameters and clinical outcome. In particular intermediate concentration groups showed a significantly better disease-free survival than the low and high concentration groups (p=0.02). We classified the patients as ''low risk'' (64 samples with p185 concentrations between 2150 and 30000 U/mg of proteins) and ''high risk'' on the basis of the results of the multivariate analysis. The p185 grouped as described showed a significant relationship with the disease free survival in multivariate analysis. Although the data must be consider ed as preliminary, they suggest the possibility of identifying more appropriately the high risk-patients through the biochemical determination of p185.