Pilot Study of the Sensitivity and Specificity of the DNA Integrity Assay for Stool-based Detection of Colorectal Cancer in Malaysian Patients

Abstract

Background: To assess the diagnostic potential of tumor-associated high molecular weight DNA in stool samples of 32 colorectal cancer (CRC) patients compared to 32 healthy Malaysian volunteers by means of polymerase chain reaction (PCR). Methods: Stool DNA was isolated and tumor-associated high molecular weight DNA (1.476 kb fragment including exons 6-9 of the p53 gene) was amplified using PCR and visualized on ethidium bromide-stained agarose gels. Results: Out of 32 CRC patients, 18 were positive for the presence of high molecular weight DNA as compared to none of the healthy individuals, resulting in an overall sensitivity of 56.3% with 100% specificity. Out of 32 patients, 23 had tumor on the left side and 9 on the right side, 16 and 2 being respectively positive. This showed that high molecular weight DNA was significantly (p = 0.022) more detectable in patients with left side tumor (69.6% vs 22.2%). Out of 32 patients, 22 had tumors larger than 1.0 cm, 18 of these (81.8%) being positive for long DNA as compared to not a single patient with tumor size smaller than 1.0 cm (p <0.001). Conclusion: We detected CRC-related high molecular weight p53 DNA in stool samples of CRC patients with an overall sensitivity of 56.3% with 100% specificity, with a strong tumor size dependence.

Performance evaluation of stool DNA methylation tests in colorectal cancer screening: a systematic review and meta‐analysis

“…Two hundred and thirty‐four records were excluded during the screening and 78 records were assessed for eligibility through full‐text articles. After excluding 17 records (reviews and commentaries), 61 articles were included in the qualitative synthesis of data [13–72]. Thirteen studies [60–72] were further excluded for different reasons.…”

“…Data on 76 single genes and 17 combinations of genes were available for quantitative synthesis. The vast majority of included studies were Sackett phase 2 case–control studies with the Oxford Centre for Evidence‐Based Medicine level of evidence 2c [13–57], whereas two studies were Sacket phase 3 cross‐sectional screening studies with 2b level of evidence [58,59]. The risk of bias and applicability concerns summary and graph of the included studies are presented in Supplements .…”