ENZYME-LINKED-IMMUNOSORBENT-ASSAY OF PS2 IN BREAST CANCERS, BENIGN-TUMORS, AND NORMAL BREAST TISSUES - CORRELATION WITH PROGNOSIS AND ADJUVANT HORMONE-THERAPY

An enzyme-linked immunosorbent assay using monoclonal and polyclonal a ntibodies against recombinant pS2 was devised. It was used to measure pS2 concentration in the cytosol of 339 breast cancers, 15 fibroadenom as, 16 cases of benign breast disease, and 6 normal breast tissues. Th e mean value of pS2 concentration was higher in cancer, but the protei n could be detected readily in benign tumors and even in normal breast . The concentration of pS2 was significantly lower in postmenopausal w omen and tumors of differentiation Grade 3. The pS2 concentration was correlated strongly with the presence of estrogen receptors (ER) and p rogesterone receptors (PR). No correlation was observed with the size, histologic type of the tumor, and lymph node status. The prognostic v alue of pS2 appeared relatively limited. It was clear cut only for a r elatively small group of patients (approximately 15%), who had low con centrations of pS2 (less-than-or-equal-to 0.32 ng/mg of protein). Thes e patients had a shorter disease-free interval and overall survival ti me. The most striking correlation was observed with the outcome of adj uvant hormone therpay. pS2 concentration was shown to be the most pote nt prognostic factor, preceding even ER.