Background/methods: The primary aims of this study were to examine the expression of metallothionein (MT) in 123 primary invasive breast carcinomas and the in situ components of these carcinomas and to assess the association between MT expression and certain socio-demographic and clinico-pathologic characteristics. MT expression was assessed using immunohistochemical procedures and semi-quantified using an immunoreactivity score.
Results: Results showed that 57.7% of the invasive tumors and 43.3% of the in situ carcinomas in the study were MT-positive. Chi-squared analyses showed that MT expression was significantly higher in the tumors of women categorized as being of 'other' race and of women with tumors of high histological grade.
Conclusions: The results of this study suggest that MT is a biomarker of tumor differentiation and aggressiveness and that MT expression may differ by race.