Smith-Ravin J, England J, Talbot I C, Bodmer W
Colorectal Cancer Unit, St Mark's Hospital, London.
Gut. 1995 Jan;36(1):81-6. doi: 10.1136/gut.36.1.81.
Colonic exfoliated epithelial cells in faecal material provide a source of human DNA which has been analysed for the presence of the tumour marker ras, in order to detect early tumour cells. The stool samples were subjected to a preliminary sample preparation step followed by centrifugation. DNA was extracted from both the centrifugation pellet and supernatant fractions, as well as from endoscopy washings, using a conventional phenol chloroform extraction method and was then purified on glass milk or spin columns. The purified DNA was amplified using mitochondrial primers and analysed for ras mutations using a non-radioactive, allele specific mismatch method. Corresponding tumour DNA was analysed for mutations using the same method. The results show that approximately 50% of the faecal samples analysed exhibited the presence of ras mutations which were also observed in the corresponding tumours. A double mutation was detected in one supernatant. Our findings represent an important stage in the development of a diagnostic test for the early detection of colorectal cancer.
粪便中的结肠脱落上皮细胞提供了人类DNA的来源，已对其进行分析以检测肿瘤标志物ras的存在，以便检测早期肿瘤细胞。粪便样本先经过初步的样本制备步骤，然后进行离心。使用传统的酚氯仿提取方法从离心沉淀和上清液部分以及内镜冲洗液中提取DNA，然后在玻璃奶或旋转柱上进行纯化。使用线粒体引物对纯化的DNA进行扩增，并使用非放射性等位基因特异性错配方法分析ras突变。使用相同方法分析相应的肿瘤DNA中的突变。结果表明，约50%被分析的粪便样本显示存在ras突变，这些突变在相应肿瘤中也被观察到。在一个上清液中检测到双突变。我们的研究结果代表了用于早期检测结直肠癌的诊断测试开发中的一个重要阶段。
