Protein oxidation in breast microenvironment: nipple aspirate fluids collected from breast cancer women contains increased protein carbonyl concentration

Background: Protein carbonyl levels are the most frequently used biomarker of protein oxidation in several human diseases, including cancer. Breast cancer, a worldwide disease with increasing incidence, develops from ductal/lobular epithelium from which nipple aspirate fluid can be collected and analysed to assess tissue metabolic activity. Our aims were to perform an exploratory investigation on the protein carbonyl accumulation in breast secretions from healthy and cancer patients and its correlation with lipid peroxidation markers