IMMUNOHISTOCHEMICAL DETECTION OF METALLOTHIONEIN IN PRIMARY BREAST CARCINOMAS AND THEIR AXILLARY LYMPH-NODE METASTASES

Metallothioneins (MTs) are low-molecular-weight proteins with specific binding for group II metal ions. MTs are involved in the detoxificati on of metals, but can also play a role in protection of the cell again st certain anticancer agents and from damage of irradiation. High expr ession of MTs in primary breast carcinomas has been found to be associ ated with poorer prognosis. Expression of MT (MT) was examined immunoh istochemically in 160 breast carcinomas and their concomitant lymph no de metastases. The immunoreactivity appeared to be independent of the length of fixation when the section was microwaved before incubation w ith the primary antibody, a monoclonal antibody E-9. The findings were correlated with various histopathological factors, disease free survi val and over-all survival. Patients were divided into two groups, thos e with MT over-expression (above 10% of positive tumour cells), and th ose with low MT expression (below 10% positive). MT over-expression wa s found to be correlated with postmenopausal status and inversely with positive progesterone receptor status (PgR). MT over-expression showe d statistically significant correlation with poor over-all survival. N o differences in survival were seen between pre- and postmenopausal pa tients. PgR was in univariate analysis a poor prognostic parameter In one fourth of the patients, the lymph node metastases showed increased MT expression compared with the primary tumour. These patients had a poorer, but not statistically significant different survival. MT expre ssion was not correlated to chemo- or radiation therapy. Thus, MT over -expression demonstrated immunohistochemically seems to be a potential prognostic factor for patients with lymph node positive breast carcin omas.