Quantitative profiling of CpG island methylation in human stool for colorectal cancer detection.
OBJECTIVE
The aims of this study were to investigate the use of quantitative CGI methylation data from stool DNA to classify colon cancer patients and to relate stool CGI methylation levels to those found in corresponding tissue samples.


METHODS
We applied a quantitative methylation-specific PCR assay to determine CGI methylation levels of six genes, previously shown to be aberrantly methylated during colorectal carcinogenesis. Assays were performed on DNA from biopsies of "normal" mucosa and stool samples from 57 patients classified as disease-free, adenoma, or cancer by endoscopy, and in tumour tissue from cancer patients. Additionally, CGI methylation was analysed in stool DNA from an asymptomatic population of individuals covering a broad age range (mean = 47 ± 24 years)


RESULTS
CGI methylation levels in stool DNA were significantly higher than in DNA from macroscopically normal mucosa, and a significant correlation between stool and mucosa was observed for ESR1 only. Multivariate statistical analyses using the methylation levels of each CGI in stool DNA as a continuous variable revealed a highly significant (p = 0.003) classification of cancer vs. non-cancer (adenoma + disease-free) patients (sensitivity = 65 %, specificity = 81 %).


CONCLUSIONS
CGI methylation profiling of stool DNA successfully identified patients with cancer despite the methylation status of CGIs in stool DNA not generally reflecting those in DNA from the colonic mucosa.
Institute of Food Research, Norwich Research Park, Norwich, NR4 7UA, UK. giles.elliott@ifr.ac.uk
Giles O
GO
Elliott
Ian T
IT
Johnson
Jane
J
Scarll
Jack
J
Dainty
Elizabeth A
EA
Williams
D
D
Garg
Amanda
A
Coupe
David M
DM
Bradburn
John C
JC
Mathers
Nigel J
NJ
Belshaw
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics; D018256:Adenomatous Polyps / Q000175:diagnosis / Q000235:genetics; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics; D018899:CpG Islands / Q000235:genetics*; D019175:DNA Methylation; D016002:Discriminant Analysis; D044127:Epigenesis, Genetic; D047628:Estrogen Receptor alpha / Q000235:genetics; D005243:Feces; D005260:Female; D017491:Genes, APC; D005819:Genetic Markers; D006801:Humans; D016015:Logistic Models; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009363:Neoplasm Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction
D048868:Adaptor Proteins, Signal Transducing; D014408:Biomarkers, Tumor; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D005819:Genetic Markers; C501486:MLH1 protein, human; D008565:Membrane Proteins; D009363:Neoplasm Proteins; D009687:Nuclear Proteins; C423567:TMEFF2 protein, human; D000070957:MutL Protein Homolog 1