Abstract
Disruption of the balanced metabolism of copper and zinc can be both a consequence and potential cause-trigger for the occurrence of many pathological conditions including cancer. Zinc is an important cofactor of many enzymes that participate in inflammatory and redox reactions and the immune response, and refers to the components of DNA transcription factors. Copper plays an important role in processes such as cuproplasia and cuproptosis, affecting the process of cell differentiation and the epithelial-mesenchymal transition of cancer cells. In this regard, the study of changes in copper and zinc in breast cancer can provide valuable information on the metabolic features of cancer cells. In this study, we investigated the metabolic relationship between the zinc and copper levels in the saliva of patients with breast cancer and the content of reactive oxygen species, the state of the antioxidant and immune systems as well as the metabolism of the amino acids Cys, His, Met, and Arg. We also considered how the content and ratio of copper and zinc in saliva changes in patients with breast cancer depend on the state of the hormonal background and the expression of hormone receptors.