Prognostication of invasive ductal breast cancer by quantification of E-cadherin immunostaining: the methodology and clinical relevance.

Abstract

We tried to improve the evaluation of E-cadherin immunostaining in paraffin sections, to distinguish the less aggressive variants of ductal infiltrating breast cancer from other variants. The method graded the membrane staining and estimated the fraction of area of cancer tissue stained at the respective staining grade, resulting in an immunohistochemical staining index. At the cut-point 0.35 the index divided all 157 patients (P=0.0188), and 57 node-positive patients (P= 0.0006) into two groups of different survival. In multivariate analysis (all patients) E-cadherin immunoscore was inferior to mitotic index (SMI) (P=0.0002), but still significant (P=0.0031). Among node-positive patients E-cadherin was even more powerful and superior (P=0.0001) to the still significant SMI (P=0.0023), and E-cadherin immunostaining and the mitotic activity (SMI) combined did not need the support of other prognosticators in the Cox model. The study suggests that E-cadherin immunostaining can be used efficiently in finding patients with favourable outcome among node-positive patients.