IMMUNOHISTOCHEMICAL EXPRESSION OF METALLOTHIONEIN IN INVASIVE BREAST-CANCER IN RELATION TO PROLIFERATIVE ACTIVITY, HISTOLOGY AND PROGNOSIS

Immunohistochemically detected metallothionein expression [MT(+)] was shown to be related to aggressive behavior of the invasive ductal carc inoma of the breast. In this study, MT expression was examined immunoh istochemically in 92 cases of invasive breast carcinoma and compared w ith immunohistochemically demonstrated estrogen receptor (ER), c-erbB- 2, Ki-67 status and clinocopathological characteristics. Of the 92 cas es examined, 27.1% (25 cases) were MT(+), and high percentages of the solid tubular subtype of invasive ductal carcinoma (47%), medullary ca rcinoma (80%), and carcinomas with spindle cell metaplasia (100%) were positive for MT. MT(+) carcinomas showed tendency to have highly atyp ical nuclei, and nuclear staining for Ki-67 antigen was found in a hig her percentage of cases than in MT(-) carcinomas. An inverse relations hip between MT(+) and ER immunoreactivity was observed. MT expression was not associated with age distribution, menopausal status, tumor siz e or lymph node metastasis. The overall survival rate in MT(+) cases w as worse than in those negative for MT, but no significant association was found. MT(+) was not associated with poor prognosis in total, est rogen receptor-negative or node-negative tumors. These findings sugges t that MT expression in breast cancer cells is related to cell-prolife rative activity, and that dedifferentiation of carcinoma cells may pla y a role in induction of MT expression.