Detection of c-Ki-ras mutations in faecal samples from sporadic colorectal cancer patients.
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.
Smith-Ravin
J
J
Colorectal Cancer Unit, St Mark's Hospital, London.
England
J
J
Talbot
I C
IC
Bodmer
W
W
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001483:Base Sequence; D003110:Colonic Neoplasms / Q000235:genetics*; D004273:DNA, Neoplasm / Q000032:analysis / Q000235:genetics; D005243:Feces / Q000737:chemistry*; D005260:Female; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012004:Rectal Neoplasms / Q000235:genetics*
D004273:DNA, Neoplasm