The effects were evaluated by measuring the activities of enzymes quinine reductase (QR), ornithine decarboxylase (ODC), and glutathione-S-transferase (GST) as well as glutathione (GSH) levels and cyclooxygenase-2 (COX-2) expression in human colorectal adenocarcinoma cell line, HT-29, treated with COS. This evidence concerns the gene PTGS2 and colorectal adenocarcinoma.