Ornithine Decarboxylase

Abstract

immediately in liquid nitrogen, stored at -70℃, and were analyzed for ODC activity within two weeks. ODC activity was assayed by a raiometric technique in which the amount of 14CO2 liberated from L-[1-14C] ornithine was measured according to the method by Fujimoto. Radioactivity of the 14CO2 trapped in the filter paper was measured in an aqueous miscible scintillant. Results: 1) Mean ODC activity(pmol CO2/hr/mg protein) of cancer, polyp and adjacent normal mucosa were 18.31, 8.05, 9.63, respectively. There was a significant difference in mean ODC activity in cancer tissue compared with polyp and adjacent normal mucosa. 2) There was no significant difference in mean ODC activity according to the size, age, morphology, differentiation and stage of cancer. But there was a statistical difference in mean ODC activity according to sex and tumor location. Mean ODC activity of males with cancer and of those with colon cancer was significantly higher than that of females with cancer and of those with rectal cancer. 3) Mean ODC activity fo cancer coexistent with adenoma was significantly higher than that of cancer with no coexisting adenoma. 4) In adjacent normal mucosa of cancer and polyp, mean ODC activity were 9.63, 6.45, respectively. There was no statistical difference in mean ODC activity between the two groups. 5) Mean ODC activity in adenomatous polyps and non-adenomatous polyps were 8.94, 7.03, respectively. Conclusion: 1he ODC activity in cancer tissue of large bowel was markedly increased compared with polyp and normal appearing colonic mucosa. But ODC activity was not correlated with invasion and differentiation of colorectal cancer. These results suggest that the elevation of ODC is correlated with cell proliferation status of colorectal cancer and reflects changes in the large bowel epithelium toward phenotypic neoplastic expression. Also, the mucosa of colorectal cancer with coexisting adenoma was shown to demonstrate a marked increase in mean ODC activity than that of colorectal cancer without adenoma. But the mucosal proliferation status of polyp was not higher than that of normal mucosa adjacent to polyp and ODC activity had no correlation to the pathologic characteristics of polyps. A broad and larger scale study on ODC activity of colorectal polyps is necessary to help predict cell proliferation of tumor