Selenium may be beneficial in reducing the risk of
cancer incidence and mortality in many
cancer types such as liver, prostate, colorectal and lung. However, despite the extensive recent research on
selenium and
selenium-containing
proteins, there are still open questions concerning their expression in certain human
cancer types, including
colorectal carcinoma. Therefore, the expression level of the
selenoproteins thioredoxin reductases 1 and 2 (TRXR-1 and TRXR-2) and
glutathione peroxidases 1 and 4 (GPX1 and GPX4) in human colon
carcinoma tissues was investigated. Up-regulation of TRXR-1 in the colon
carcinoma specimens was found both in disease stage-dependent and independent analyses. No differences were found for TRXR-2 expression levels. GPX1 was up-regulated in
carcinoma tissues at both the
protein and
mRNA levels. GPX4 was also up-regulated at the
protein level, except for the samples derived from stage III patients. The expression of TRXR-1, GPX1 and GPX4, but not TRXR-2 is differently regulated in
cancer as compared to healthy colonic tissue.