On predictivity of malignant change og familial adenomatous polyposis.

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1)Time and location specific ornithine decarboxylase(ODC)activity was measured during and after injection of DMH in rats. ODC activity of the colonic mucosa increased before development of colonic carcinoma(12 weeks from the beginning of DMH injection). The ODC activity was lowest at the rectum and highest at the cecum. Number of carcinoma was higher in the proximal colon than in the distal colon except cecum.2)ODC activity was measured on the colorectal normal mucosa, carcinoma, and polyps -of patients of colorectal carcinoma and familial adenomatous polyposts(FAP). ODC activity of adenoma was as high as carcinoma. ODC activity in colonic carcinoma was correlated with age, and ODC activity of carcinoma was higher in the younger patients than in the older patients. This was same at the normal mucosa. We concluded that ODC activity is one of indicator for showing growth activity of colonic mucosa and may be used as risk factor for development of neoplasms in the mucosa in which ODC activity is enhanced, but it will not be used to predict development of carcinoma in FAP patients.3)Loss of heterozygosity(LOH)was observed in adenomas of FAP patients on chromosome 5q(12%), 17p(8%), and 22q(2%). The frequency of LOH in the colonic carcinoma was 5q(38%), 17p(57%), 22q(35%). The frequency of LOH was correlated with the stage of carcinoma.4)p53 was not constantly stained in colonic carcinoma by immunohistochemical staining.As a result, detection of LOH or mutation on the chromosome 5q and 17p may be effective for a prediction of the malignant change of adenomas, but more practical method is to be developed.