With the development of the tumor, the expression of the cytoprotective enzymes ecNOS and COX-1 in gastric cancer decreased. When compared to less advanced tumors, advanced tumors greater than 5 cm, penetrating into or through the serosa, and having metastases to lymph nodes or distant organs exhibited considerably higher iNOS and COX-2 expression. This evidence concerns the gene NOS2 and neoplasm.