ORNITHINE DECARBOXYLASE AS A MARKER FOR PREMALIGNANCY IN THE STOMACH

Assessment of mucosal ornithine decarboxylase (ODC) activity in the hu man large bowel may be of value as a marker of potential malignant ris k. Its value as a marker of premalignancy in the upper gastrointestina l tract is less clear. Using a [C-14]-ornithine bioassay, gastric muco sal ODC activity was measured in 32 normal subjects and 22 patients wi th confirmed gastric cancer. These results were compared with 47 patie nts at increased risk of upper gastrointestinal malignancy, (32 patien ts with partial gastric resection, 15 patients with familial adenomato us polyposis). Median ODC activity in normal subjects was 371 pmol/mg protein/h, (interquartile range (IQR), 230-617). There was no variatio n with age or sex and no relation to Helicobacter pylori status. Norma l subjects had significantly lower ODC activity than patients with a g astric resection or confirmed gastric cancer, but similar to patients with familial adenomatous polyposis. Furthermore, no difference in act ivity was identified between patients with a gastric resection and est ablished gastric cancer. ODC activity was, however, significantly incr eased in areas of gastric atrophy or intestinal metaplasia, regardless of the clinical group fi om which the samples were obtained. It is co ncluded that measurement of mucosal ODC activity does not provide addi tional predictive information of malignant risk in the stomach and inv estigation of other potential biomarkers of malignancy is warranted.