Serum levels of zinc, copper, selenium and glutathione peroxidase in the different groups of colorectal cancer patients

BACKGROUND: Colorectal cancer (CRC) is considered the fourth type of cancer that causes death worldwide. Changes in the levels of zinc (Zn), copper (Cu), and selenium (Se) as well as low glutathione peroxidase (GPx) activity can lead to CRC and this study was aimed to evaluate their possible use as diagnostic markers. METHODS: CRC patients (n=90) were divided into three groups; newly diagnosed, before surgery, and after surgery. These groups were compared to healthy subjects (n=30); the mean age ±SD was 50.63±9.26 and 49.97±10.85 for CRC patients and healthy subjects, respectively. Biochemical study for serum levels of Zn and Cu was measured by FAAS, Se was measured by HGAAS, and ELISA for GPx. RESULTS: Zn, Cu, Se and GPx were significantly lower in all CRC patient groups, except for the after surgery group which showed no differences for Zn and GPx as compared to the healthy subjects. Positive correlations were found between Se and Zn and between Se and GPx (r=0.71, r=0.42; P<0.01, respectively) in all CRC patient groups. A receiver operating characteristic (ROC) curve analysis was applied for the newly diagnostic group showing all the parameters that can be used as diagnostic markers for CRC. CONCLUSION: The present results conclude that Zn, Cu Se, and GPx can be used as diagnostic markers for CRC, where the decrease of these parameters may be associated with an increased risk of CRC and as indicators of the response to therapy.