On predictivity of malignant change og familial adenomatous polyposis.

1)测定大鼠注射DMH时、后的时间、位置特异性鸟氨酸脱羧酶（ODC）活性。结肠黏膜ODC活性在结肠癌发生前（注射DMH开始后12周）升高。ODC活性在直肠最低，盲肠最高。除盲肠外，近端结肠癌数高于远端结肠癌数。2)测定结直肠癌和家族性腺瘤性息肉（FAP）患者结肠正常黏膜、癌和息肉的ODC活性。腺瘤的ODC活性与癌相当。结肠癌中ODC活性与年龄相关，年轻患者的ODC活性高于老年患者。正常粘膜亦是如此。我们认为ODC活性是显示结肠粘膜生长活性的指标之一，可能作为ODC活性增强的粘膜肿瘤发生的危险因素，但不能用于预测FAP患者的肿瘤发展。3) FAP患者腺瘤在5q（12%）、17p（8%）和22q（2%）染色体上存在杂合性缺失（LOH）。结肠癌LOH发生率分别为5q（38%）、17p（57%）、22q（35%）。LOH的发生频率与肿瘤分期有关。4)免疫组化染色在结肠癌中p53未被持续染色。因此，检测LOH或5q和17p染色体突变可能是预测腺瘤恶性变化的有效方法，但更实用的方法有待开发。

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.