Fig. 1.

Shifting trace element concentrations including selenium (Se), iron (Fe), copper (Cu), and zinc (Zn) in serum (depicted as blood vessel) and tumor tissue (depicted as cell) of cancer patients based on case-control studies published within the last years and referred within this review. Trace element differences of cancer patients compared to controls are illustrated by size deviations from the reference circle. ¹ particularly robust in breast cancer studies, ² particularly robust in prostate cancer, ³ depending on cancer type contradictory changes occur.