K-ras and p53 mutations in DNA extracted from colonic epithelial cells exfoliated in faeces of patients with colorectal cancer.
BACKGROUND
Exfoliated colonic epithelial cells in faeces provide a source of human DNA which may be analysed for the presence of tumour-induced modification.


OBJECTIVE
In the present study we investigated K-ras and p53 mutations in faeces of patients with colorectal carcinoma, to verify whether analysis of these mutations might identify a high percentage of patients with colorectal cancer.


METHODS
Faeces, tumour and normal mucosa samples were taken from 26 patients. Polymerase chain reaction amplification and restriction enzyme analysis were performed to detect K-ras mutations; p53 gene mutations were identified by using polymerase chain reaction amplification and single strand conformation polymorphism.


RESULTS
We were able to amplify the K-ras gene and exons 5-9 of the p53 gene in 100% of the faecal samples studied. K-ras and p53 gene mutations were detected in faeces in 26.9% and 50% of the cases, respectively. The two mutations were present together in 5 out of 26 patients. There was full agreement between the K-ras and p53 pattern observed in faecal DNA and that in tumour tissue DNA.


CONCLUSIONS
Application of K-ras and p53 mutation gene analysis in the faeces may have clinical applications in the future. Since this genetic analysis is able to detect only 57.7% of patients with colorectal cancer, the study of other genes involved in colorectal carcinogenesis is necessary.
Notarnicola
M
M
Laboratory of Biochemistry, IRCCS Scientific Institute for Digestive Diseases, S. de Bellis Castellana G., BA, Italy.
Cavallini
A
A
Cardone
R
R
Pezzolla
F
F
Demma
I
I
Di Leo
A
A
D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics; D003106:Colon; D015179:Colorectal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D004252:DNA Mutational Analysis; D017931:DNA Primers / Q000737:chemistry; D004273:DNA, Neoplasm / Q000032:analysis* / Q000235:genetics; D004847:Epithelial Cells / Q000378:metabolism* / Q000473:pathology; D005243:Feces / Q000166:cytology; D005260:Female; D016158:Genes, p53 / Q000235:genetics*; D011905:Genes, ras / Q000235:genetics*; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism* / Q000473:pathology; D008297:Male; D008875:Middle Aged; D009154:Mutation; D016133:Polymerase Chain Reaction; D018807:Polymorphism, Single-Stranded Conformational
D014408:Biomarkers, Tumor; D017931:DNA Primers; D004273:DNA, Neoplasm