PRIMARY CHEMOTHERAPY IN BREAST INVASIVE-CARCINOMA - PREDICTIVE VALUE OF THE IMMUNOHISTOCHEMICAL DETECTION OF HORMONAL RECEPTORS, P53, C-ERBB-2, MIB1, PS2 AND GST-PI

Primary chemotherapy in operable breast invasive carcinoma enables tum our reduction and conservative surgery. In order to search for one or more biological factors capable of predicting tumour behaviour under p rimary chemotherapy, and subsequent patient survival, an immunohistoch emical study was performed with specific antibodies to p53, c-erbB-2 ( Her-2/neu), Mib1 (antiKi-67), pS2, GST pi, oestrogen receptors (ERs) a nd progesterone receptors (PRs). Core biopsies, obtained before primar y chemotherapy, were available from a series of 128 breast invasive ca rcinomas treated between January 1985 and April 1989, with a median fo llow-up of 93.3 months. Univariate statistical analysis showed that ne gative ER detection by immunohistochemistry (IHC) was highly correlate d with chemosensitivity (P=0.001). A high percentage of Mib1-positive tumour cells (>40%), as well as initial tumour size less than 4 cm, we re also correlated with tumour responsiveness to chemotherapy (P=0.009 and P=0.03). By multivariate analysis IHC-ER, Mib1 and initial tumour size were independent predictors, the last parameter being the most i mportant. Concerning subsequent patient survival, c-erbB-2 overexpress ion, as detected by IHC, was significant with respect to overall survi val (OS) (P=0.0006), disease-free interval (DFI) (P=0.03) and metastas is-free interval (MFI) (P=0.008) by univariate analysis. Furthermore, c-erbB-2 was the major independent prognostic factor for OS and MFI by multivariate analysis.