Variation in Blood and Colorectal Epithelia's Key Trace Elements Along with Expression of Mismatch Repair Proteins from Localized and Metastatic Colorectal Cancer Patients

Colorectal cancer (CRC) is an increasingly common medical issue affecting millions worldwide, and contribution of the body's trace elements to CRC is arguable. The concentrations and buffered status of selenium, iron, copper, zinc, and phosphorus in blood and large intestinal tissues of CRC patients are, respectively, variable and vital for cell physiology. The aim of this study was to assess selenium, iron, copper, zinc, and phosphorus variations in blood and colorectal epithelia along with examining the expression of mismatch repair proteins in CRC patients with/without metastasis for potential diagnosis/therapy. Concentrations of selenium, iron, copper, zinc, and phosphorus in blood of healthy versus CRC patients and colorectal epithelia (adenocarcinomatous versus non-adenocarcinomatous/control) were measured in 40 CRC patients (55.87 +/- 11.9 years old) with/without metastasis before surgery using ICP-OES. Mismatch repair (MMR) protein expression was analyzed through histopathological/immunohistochemistry assays, which was sparse in 5 CRC patient's colorectal tissues (12%). Compared with healthy individuals, blood and colorectal tissue's levels of phosphorus, copper, and iron were significantly higher in the CRC patients, and more pronounced in metastatic CRC patients; conversely, blood and colorectal tissue's selenium levels were significantly lower in metastatic patients. Unlike blood zinc, cancerous colorectal tissue's zinc concentration was significantly lower in CRC patients compared to healthy control cohorts. There was no significant difference on the measured elements in samples from CRC patients with MMR- compared to CRC patients with MMR+. Receiver operating characteristic analysis revealed a correlation of blood iron, zinc, copper, and phosphorus to CRC, and inappropriately low levels of blood and colorectal selenium correlated with exacerbated metastasis. Altered levels of selenium, iron, copper, zinc, and phosphorus in vivo may impact the pathogenesis and detection of CRC, and their diagnostic/therapeutic potential in CRC would be revealing.