Expression of Metallothionein in Node‐Negative Breast Cancer Correlates with Poor Prognosis

Abstract: Metallothionein (MT) is a cysteine‐rich protein that binds metals and is present in a number of normal cells, mainly during fetal life. It has been suggested that the developmental profile of metallothionein is similar to oncofetal gene products, and therefore, it could be potentially used as a prognostic tumor marker. We explored this concept by performing immuno‐histochemical stain for metallothionein in 155 axillary lymph node‐negative breast carcinomas. Traditional tumor prognosticators of breast cancer including histologic type, nuclear grade, and estrogen receptor content were also analyzed to determine whether or not metallothionein is an independent marker of behavior. Moderate to strong metallothionein immunoreactivity of tumor cells correlated with decreased disease free (p < 0.02), and overall survivals (p < 0.03). No correlation was found between MT and histologic type and nuclear grade of tumors. Similarly, there was no statistically significant relationship between MT and estrogen receptor contents. It is concluded that overexpression of metallothionein is an independent indicator of poor prognosis in node‐negative breast carcinomas.