A simplified, non-invasive fecal-based DNA integrity assay and iFOBT for colorectal cancer detection
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Neoplasia cells exfoliated from colorectal epithelium have dysfunctional apoptotic mechanisms, thus it is possible to identify high-molecular weight DNA fragments in feces. This prospective single-center study was performed to evaluate the sensitivity and specificity of fecal-based DNA integrity versus immunological fecal occult blood test (iFOBT) and calprotectin for colorectal cancer (CRC) and adenoma detection.
Feces were collected from 204 subjects and DNA integrity was quantified by quantitative-denaturing high performance liquid chromatography (QdHPLC). Calprotectin and iFOBT were assessed using commercial kits. The diagnostic performance was calculated by receiver operating characteristic (ROC) curves analysis.
A total of 192 fecal specimens were analyzed and 12 samples were excluded due to DNA degradation. We found long DNA (L-DNA) occurrence in feces with a sensitivity of 86% (n = 24/28) and a specificity of 81% for CRC detection. To minimize false-positive cases of the developed test, area under the curve of ROC was evaluated such that the specificity was increased to 92% with decreased sensitivity to 79%, p = 0.0001 for CRC detection. iFOBT was positive in 51% (n = 14/27) while calprotectin was positive in 75% (n = 18/27). The combination of iFOBT and L-DNA identified a greater number of CRC cases with a sensitivity of 89% and a specificity of 95%, p < 0.001. The combination also improved the sensitivity of polyps, particularly high-grade dysplasia and advanced adenoma (33%, p = 0.0015) as opposed to a single evaluation assay (17–21%).
This study illustrates the usefulness of fecal DNA integrity assay by QdHPLC as a non-invasive, easy-to-perform, and reproducible method with a high level of sensitivity in detecting individuals with colorectal neoplasia. Combination of iFOBT and L-DNA improves the sensitivity for CRC and adenoma detection.
KeywordsCRC DIA Feces iFOBT L-DNA QdHPLC-DIA
Fecal occult blood test
DNA integrity assay
Quantitative denaturing high performance liquid chromatography
Receiver operating characteristic
This work was supported by grants from the University Hospital Tor Vergata, University of Rome. MK was supported by the pre-doctoral scholarship for foreign student under the International Italian Government University scholarship. We thank Paolo Zaccagna from Transgenomic Inc. for his invaluable suggestions, comments, as well as technical support on the QdHPLC application.
Conflict of interest
The authors state that there are no conflicts of interest regarding the publication of this article. Support provided by Transgenomic Inc. played no role in the study design; in the collection, analysis, and interpretation of data; in the writing of the report; or in the decision to submit the report for publication.
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