While toxic in high concentrations, copper is essential to life as a trace element. Many tumors require significantly more copper than healthy cells for growth—a possible new point of attack for cancer treatment. While toxic in high concentrations, copper is essential to life as a trace element. Many tumors require significantly more copper than healthy cells for growth—a possible new point of attack for cancer treatment. Bio & Medicine Nanomaterials Phys.org – latest science and technology news stories