E-cadherin quantitative immunocytochemical assays in breast carcinomas.

The reduction of E-cadherin expression, which is involved in the initial step of invasion and metastasis of cancer, was investigated in 218 human breast carcinomas. Quantitative immunohistochemical assays (ICAs) were performed on frozen sections. Quantitation was assessed by processing digitized microscopic images of immunoreactions using a computerized system of image analysis (SAMBA). The results were correlated with clinicopathological data and quantitative immunodetection of other molecules. E-cadherin expression was significantly (P < 0.001) stronger in ductal carcinomas than in lobular carcinomas and stronger (P < 0.01) in low grades than in high grades, but E-cadherin was independent of lymph node status and tumour size. Also an inverse significant (P < 0.01) relationship was observed between E-cadherin expression on tissue sections and positive immunoreactions with anti-P53, MIB1 (growth fraction), and anti-c-erb-B2 product. Conversely, strong positive and anti-E-cadherin immunoreactions correlated with strong positive anti-ER and anti-PR immunoreactions (P < 0.01). No relationship was observed between E-cadherin and the results of quantitative ICAs of cathepsin D, CD31, and P-glycoprotein, assessed on consecutive sections from the same frozen tissue samples. The results show that preserved E-cadherin expression correlates with high degree of tumour differentiation, low proliferative activity, and low expression of prognostic markers. The deregulation of E-cadherin is independent of other steps of tumour invasion, such as protease digestion of extracellular matrix and angiogenesis.