Immunoenzymatic assay of erbB2 protein in cancer and non-malignant breast tissue. Relationships with clinical and biochemical parameters.

The erbB2-encoded protein p185 was determined in 130 breast cancer specimens and in 29 non-malignant breast tissues using a recently available ELISA method. The assay showed good characteristics of precision and accuracy. In the non-malignant tissue p185 concentrations were normally distributed and directly correlated with estrogen receptors (ER) and progesterone receptors (PR). In cancer tissue p185 showed higher concentrations than in non-malignant tissue. No relationships were found between p185 and the main clinical and pathological parameters, except that a direct association with nuclear grade was found. We have categorized the breast cancer samples according to p185 concentrations as p185-negative (concentrations lower than the higher non-malignant tissue) and p185-positive. Our data suggested a different behaviour of p185 in samples with low or high p185 concentrations. Indeed, in p185-negative samples the concentrations were directly correlated with both ER and PR. Conversely, p185-positive samples were directly associated with node status and pT, and inversely associated with ER and PR.