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 detoxification of metals, but can also play a role in protection of the cell against certain anticancer agents and from damage of irradiation. High expression of MTs in primary breast carcinomas has been found to be associated with poorer prognosis. Expression of MT (MT) was examined immunohistochemically in 160 breast carcinomas and their concomitant lymph node metastases. The immunoreactivity appeared to be independent of the length of fixation when the section was microwaved before incubation with the primary antibody, a monoclonal antibody E-9. The findings were correlated with various histopathological factors, disease-free survival and over-all survival. Patients were divided into two groups, those with MT over-expression (above 10% of positive tumour cells), and those with low MT expression (below 10% positive). MT over-expression was found to be correlated with postmenopausal status and inversely with positive progesterone receptor status (PgR). MT over-expression showed statistically significant correlation with poor over-all survival. No differences in survival were seen between pre- and postmenopausal patients. 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 expression was not correlated to chemo- or radiation therapy.(ABSTRACT TRUNCATED AT 250 WORDS)