A simplified, non-invasive fecal-based DNA integrity assay and iFOBT for colorectal cancer detection

Int J Colorectal Dis. 2011 May;26(5):583-92. doi: 10.1007/s00384-010-1128-x. Epub 2011 Jan 12.


Purpose: 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.

Methods: 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.

Results: 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%).

Conclusions: 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.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenoma / diagnosis
  • Adult
  • Aged
  • Aged, 80 and over
  • Biological Assay / methods*
  • Chromatography, High Pressure Liquid
  • Colonoscopy
  • Colorectal Neoplasms / diagnosis*
  • DNA / analysis*
  • Feces / chemistry*
  • Female
  • Humans
  • Leukocyte L1 Antigen Complex / metabolism
  • Male
  • Middle Aged
  • Nucleic Acid Denaturation
  • Occult Blood*
  • ROC Curve
  • Regression Analysis
  • Sensitivity and Specificity


  • Leukocyte L1 Antigen Complex
  • DNA