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Updated: Mar 23, 2026
Evaluation of Colorectal Cancer Risk and Prevalence by Stool DNA Integrity Detection
Published on: June 8, 2020
Increased Free Circulating DNA Integrity Index as a Serum Biomarker in Patients with Colorectal Carcinoma
Dina El-Gayar1, Nevine El-Abd, Noha Hassan
1Clinical and Chemical Pathology, Faculty of Medicine, Cairo University, Cairo, Egypt
Background:
Cell-free DNA circulating in blood is a candidate biomarker for malignant tumors. Unlike uniformly truncated DNA released from apoptotic non diseased cells, DNA released from necrotic cancer cells varies in size.
Objectives:
To measure the DNA integrity index in serum and the absolute DNA concentration to assess their clinical utility as potential serum biomarkers for colorectal carcinoma (CRC) compared to CEA and CA19-9.
Materials And Methods:
Fifty patients with CRC, 10 with benign colonic polyps and 20 healthy sex and age matched volunteers, were investigated by real time PCR of ALU repeats (ALU q-PCR) using two sets of primers (115 and 247 bp) amplifying different lengths of DNA fragments. The DNA integrity index was calculated as the ratio of q-PCR results of ALU 247/ ALU 115bp.
Results:
Serum DNA integrity was statistically significantly higher in CRC patients compared to the benign and control groups (p<0.001). ROC curves for differentiating CRC patients from normal controls and benign groups had areas under curves of 0.90 and 0.85 respectively.
Conclusions:
The DNA integrity index is superior to the absolute DNA concentration as a potential serum biomarker for screening and diagnosis of CRC. It may also serve as an indicator for monitoring the progression of CRC patients. Combining CEA and CA19-9 with either of the genetic markers studied is better than either of them alone.
