Quantitative fluorescence determination of long-fragment DNA in stool as a marker for the early detection of colorectal cancer.
BACKGROUND
A variety of molecular markers have been evaluated for the development of a non-invasive approach to the diagnosis of colorectal cancer. We aimed to validate the diagnostic accuracy, using the same threshold as in the previous pilot study, of fluorescent long DNA test as a relatively simple and inexpensive tool for colorectal cancer detection.


METHODS
A case-control study was conducted on 100 healthy subjects and 100 patients at first diagnosis of colorectal cancer. Human long-fragment DNA in stool was quantified by fluorescence primers and a standard curve and expressed in DNA nanograms.


RESULTS
We validated the 25-ng value, which emerged as the most accurate cut-off in the pilot study, obtaining 79% (95% CI, 71-87%) sensitivity and 89% (95% CI, 83-95%) specificity. Specificity was very high for all cut-off values (15-40 ng) analyzed, ranging from 78 to 96%. Sensitivity was only slightly lower, reaching 84% at the lowest cut-off and maintaining a good level at the higher values. Diagnostic potential was independent of gender, age and tumor site.


CONCLUSIONS
Fecal DNA analysis is a non-invasive and fairly simple test showing high diagnostic potential. These characteristics, together with the small amount of stool required, make it potentially suitable to be used alongside or as an alternative to current non-invasive screening approaches. Our next step will be to validate these results in a large-scale cohort study of a screening population, which is needed prior to implementation into clinical practice.
Calistri
Daniele
D
Istituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori, Via Maroncelli 40, Meldola (FC), Italy. d.calistri@irst.emr.it
Rengucci
Claudia
C
Molinari
Chiara
C
Ricci
Enrico
E
Cavargini
Elena
E
Scarpi
Emanuela
E
Milandri
Gian Luigi
GL
Fabbri
Carla
C
Ravaioli
Alberto
A
Russo
Antonio
A
Amadori
Dino
D
Silvestrini
Rosella
R
D025601:Adenomatous Polyposis Coli Protein / Q000235:genetics; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000235:genetics*; D016022:Case-Control Studies; D015179:Colorectal Neoplasms / Q000175:diagnosis* / Q000235:genetics*; D004247:DNA / Q000235:genetics*; D017931:DNA Primers / Q000235:genetics; D055088:Early Detection of Cancer; D005243:Feces / Q000737:chemistry*; D005260:Female; D005456:Fluorescent Dyes / Q000737:chemistry; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D016159:Tumor Suppressor Protein p53 / Q000235:genetics
D025601:Adenomatous Polyposis Coli Protein; D014408:Biomarkers, Tumor; D017931:DNA Primers; D005456:Fluorescent Dyes; D016159:Tumor Suppressor Protein p53; D004247:DNA