ENZYME-LINKED-IMMUNOSORBENT-ASSAY OF HER-2 NEU GENE-PRODUCT (P185) INBREAST-CANCER - ITS CORRELATION WITH SEX STEROID-RECEPTORS, CATHEPSIN-D AND HISTOLOGIC GRADES/

One hundred and nine primary breast cancers were analysed to assess th e presence of the HER-2/neu gene product (p185), the oestrogen (ER) an d the progesterone (PR) receptors, and the total cathepsin D status. A n enzyme-linked immunosorbent assay (ELISA kit, Oncogene Science Inc.) was used for the evaluation of p185 in pellets obtained after a 100 0 00 x g centrifugation, ER and PR were measured by enzyme immunoassay ( EIA kit, Abbott Laboratories), and the total cathepsin D content was e valuated by immunoradiometric. assay (IRMA kit, CIS Biointernational). We showed that the ELISA kit is feasible to quantify the p185 present in breast cancer cell membranes, and that the detector antibody recog nises a protein of approximately M(r) 185 000. The detected antigen wa s inversely related to both ER and PR, but it did not correlate to tot al cathepsin D. No significant differences were found in the expressio n of p185, ER, PR, cathepsin D between infiltrating ductal carcinomas without special features (NOS) and non-ductal (non-NOS) carcinomas. Ne vertheless, in NOS carcinomas, a trend was observed in the p185 levels expressed by the tumours with different histological grades, in that p185 concentration was higher in the poorly differentiated grade 3 wit h respect to grade 2 and grade 1.