Metals and breast cancer: risk factors or healing agents?

Metals and metal compounds are part of our environment. Several metals are essential for physiological functions (e.g., zinc or magnesium); while the beneficial effects of others are uncertain (e.g., manganese), some metals are proven to be toxic (e.g., mercury, lead). Additionally there are organic metal compounds; some of them are extremely toxic (e.g., trimethyltin, methylmercury), but there is very little knowledge available how they are handled by organisms. Scientific evidence indicates that long-term exposure to (some) metallic compounds induces different forms of cancer, including breast cancer. On the other side, several metal compounds have clinical use in treating life-threatening diseases such as cancer. In this paper we discuss the recent literature that shows a correlation between metal exposure and breast cancer.