Combination analysis of hypermethylated SFRP1 and SFRP2 gene in fecal as a novel epigenetic biomarker panel for colorectal cancer screening

KCNQ5 and C9orf50 Methylation in Stool DNA for Early Detection of Colorectal Cancer

Background

Aberrant DNA methylation has emerged as a class of promising biomarkers for early colorectal cancer (CRC) detection, but the performance of methylated C9orf50 and methylated KCNQ5 in stool DNA has never been evaluated.

Methods

Methylation specific quantitative PCR (qPCR) assays for methylated C9orf50 and methylated KCNQ5 were developed. The methylation levels of C9orf50 and KCNQ5 in 198 CRC patients, 20 advanced adenoma (AA) patients, 101 small polyp (SP) patients, and 141 no evidence of disease (NED) subjects were analyzed.

Results

The methylation levels of both KCNQ5 and C9orf50 genes were significantly higher in CRC and AA groups than those in SP and NED groups, but showed no significant difference among different stages of CRC. The sensitivities of methylated KCNQ5 and methylated C9orf50 for CRC detection were 77.3% (95% CI: 70.7–82.8%) and 85.9% (95% CI: 80.0–90.2%) with specificities of 91.5% (95% CI: 85.3–95.3%) and 95.0% (95% CI: 89.7–97.8%), respectively. When C9orf50 and methylated KCNQ5 were combined, the clinical performance for CRC detection was similar to that of methylated C9orf50 alone.

Conclusions

Stool DNA based methylated C9orf50 test has the potential to become an alternative approach for CRC screening and prevention.

A systematic review and quantitative assessment of methylation biomarkers in fecal DNA and colorectal cancer and its precursor, colorectal adenoma

Colorectal cancer (CRC) arises from accumulated genetic and epigenetic alterations, which provide the possibility to identify tumor-specific biomarkers by analyzing fecal DNA. Methylation status in human genes from tumor tissue is highlighted as promising biomarker in the early detection of CRC. A number of studies have documented altered methylation levels in DNA extracted from stool samples, but generated heterogeneous results. We performed a systematic review and quantitative assessment of existing studies to compare levels of DNA methylation in most frequently studied genes and their diagnostic value in CRC and its precursor, colorectal adenoma, with their counterparts in healthy subjects. Robust searches of the literature were performed in our study with explicit strategies and definite inclusion/exclusion criteria. Pooled data revealed that methylation levels of SFRP2, SFRP1, TFPI2, BMP3, NDRG4, SPG20, and BMP3 plus NDRG4 genes exceeded a sensitivity of 70% and a specificity of 80% for CRC detection. The DOR of the seven candidate biomarkers ranged from 19.80 to 334.33, indicating a good diagnostic power in discriminating cancer from normal tissues. The AUC range was from 0.88 to 0.95, indicating a good or very good discriminatory performance. When test results for BMP3 and NDRG4 were combined, the DOR of CRC detection was 98.36, which was higher than that for BMP3 and NDRG4 separately. As for adenoma detection, the DOR of methylated NDRG4 is higher than that for CRC (CRC vs. adenoma: 54.86 vs. 57.22). Both the sensitivity and specificity of NDRG4 for adenoma detection exceeded 70%. These findings demonstrate the eligibility and feasibility of DNA methylation as a minimally invasive biomarker in feces in the diagnosis of CRC and adenoma. The use of DNA from human stools has the potential to be readily applicable to detect aberrant DNA methylation levels among many subjects for CRC early screening.

Colorectal adenoma and cancer detection based on altered methylation pattern of SFRP1, SFRP2, SDC2, and PRIMA1 in plasma samples

Aberrant methylation is one of the most frequent epigenetic alterations that can contribute to tumor formation. Cell-free DNA can originate from tumor tissue; therefore, the evaluation of methylation markers in cell-free DNA can be a promising method for cancer screening. Our aim was to develop a panel of biomarkers with altered methylation along the colorectal adenoma-carcinoma sequence in both colonic tissue and plasma. Methylation of selected CpG sites in healthy colonic (n = 15), adenoma (n = 15), and colorectal cancer (n = 15) tissues was analyzed by pyrosequencing. MethyLight PCR was applied to study the DNA methylation of SFRP1, SFRP2, SDC2, and PRIMA1 gene promoters in 121 plasma and 32 biopsy samples. The effect of altered promoter methylation on protein expression was examined by immunohistochemistry. Significantly higher (P < 0.05) DNA methylation levels were detected in the promoter regions of all 4 markers, both in CRC and adenoma tissues compared with healthy controls. Methylation of SFRP1, SFRP2, SDC2, and PRIMA1 promoter sequences was observed in 85.1%, 72.3%, 89.4%, and 80.9% of plasma samples from patients with CRC and 89.2%, 83.8%, 81.1% and 70.3% from adenoma patients, respectively. When applied as a panel, CRC patients could be distinguished from controls with 91.5% sensitivity and 97.3% specificity [area under the curve (AUC) = 0.978], while adenoma samples could be differentiated with 89.2% sensitivity and 86.5% specificity (AUC = 0.937). Immunohistochemical analysis indicated decreasing protein levels of all 4 markers along the colorectal adenoma-carcinoma sequence. Our findings suggest that this methylation biomarker panel allows non-invasive detection of colorectal adenoma and cancer from plasma samples.

A pan-cancer analysis of secreted Frizzled-related proteins: re-examining their proposed tumour suppressive function

Secreted frizzled-related proteins (SFRPs), containing five family members (SFRPs 1-5) are putative extracellular Wnt inhibitors. Given their abilities to inhibit Wnt signalling, as well as the loss of SFRP1 in many cancers, this family is generally considered to be tumour suppressive. In this study we analyzed gene expression, promoter methylation and survival data from over 8000 tumour and normal samples from 29 cancers in order to map the context-specific associations of SFRPs 1-5 with patient survival, gene silencing and gene expression signatures. We show that only SFRP1 associates consistently with tumour suppressive functions, and that SFRP2 and SFRP4 typically associate with a poor prognosis concomitant with the expression of genes associated with epithelial-to-mesenchymal transition. Moreover, our results indicate that while SFRP1 is lost in cancer cells via the process of DNA methylation, SFRP2 and 4 are likely derived from the tumour stroma, and thus tend to increase in tumours as compared to normal tissues. This in-depth analysis highlights the need to study each SFRP as a separate entity and suggests that SFRP2 and SFRP4 should be approached as complex matricellular proteins with functions that extend far beyond their putative Wnt antagonistic ability.

Methylation of SFRP2 gene as a promising noninvasive biomarker using feces in colorectal cancer diagnosis: a systematic meta-analysis

Methylation of secreted frizzled-related protein genes (SFRP) associated with the Wnt signaling pathway has previously been reported. However, the diagnostic role of SFRP methylation in colorectal cancer (CRC) remains unclear. A systematic search was performed to identify eligible articles for analysis. The pooled OR showed that SFRP1, SFRP2, SFRP4 and SFRP5 methylation was significantly higher in CRC and benign mucosal lesions than in normal colonic mucosa. When CRC was compared to benign mucosal lesions, SFRP1 and SFRP2 methylation had a significantly higher OR, but methylated SFRP4 and SFRP5 had a similar OR. Moreover, the pooled sensitivity, specificity and AUC (area under the curve) of methylated SFRP2 in feces of patients with CRC vs. healthy subjects was 0.71, 0.94 and 0.94, respectively. Therefore, methylation of SFRP1 and SFRP2 may be significantly correlated with CRC. However, in a study with small sample size, methylated SFRP4 and SFRP5 were not shown to be closely associated with CRC. Additionally, detection of SFRP2 methylation in feces presents a potential noninvasive biomarker for CRC diagnosis.

The Diagnostic Performance of Stool DNA Testing for Colorectal Cancer: A Systematic Review and Meta-Analysis

This meta-analysis was designed to evaluate the diagnostic performance of stool DNA testing for colorectal cancer (CRC) and compare the performance between single-gene and multiple-gene tests.MEDLINE, Cochrane, EMBASE databases were searched using keywords colorectal cancers, stool/fecal, sensitivity, specificity, DNA, and screening. Sensitivity analysis, quality assessments, and performance bias were performed for the included studies.Fifty-three studies were included in the analysis with a total sample size of 7524 patients. The studies were heterogeneous with regard to the genes being analyzed for fecal genetic biomarkers of CRC, as well as the laboratory methods being used for each assay. The sensitivity of the different assays ranged from 2% to 100% and the specificity ranged from 81% to 100%. The meta-analysis found that the pooled sensitivities for single- and multigene assays were 48.0% and 77.8%, respectively, while the pooled specificities were 97.0% and 92.7%. Receiver operator curves and diagnostic odds ratios showed no significant difference between both tests with regard to sensitivity or specificity.This meta-analysis revealed that using assays that evaluated multiple genes compared with single-gene assays did not increase the sensitivity or specificity of stool DNA testing in detecting CRC.

Variation risks of SFRP2 hypermethylation between precancerous disease and colorectal cancer

DNA hypermethylation of secreted frizzled-related protein 2 (SFRP2) gene associated with the Wnt signaling pathway has been studied previously. However, the risk size and changing rules between colorectal cancer (CRC) and SFRP2 hypermethylation from precancerous disease to CRC remain unclear. The aim of work was therefore to investigate the risk size and changing rule based on detections on large numbers of tissue and feces samples. Association study and meta-analysis were performed to analyze the risk size of SFRP2 hypermethylation in tissue and fecal detections from 2,912 samples, including 1,436 patients with CRC, 866 patients with colon adenomas or polyps, and 610 samples with both normal controls. Based on normal controls as standard reference, the analysis showed that SFRP2 hypermethylation in CRC and adenoma tissues had a significantly higher risk with 92.81 (28.76-299.45) and 22.46 (4.13-122.04) odds ratio (OR) (95 % confidence interval (CI)) respectively, and that the risk sizes of SFRP2 hypermethylation in CRC and adenoma patients were 41.86 (18.91-92.67) and 11.76 (6.98-19.84) of OR (95 % CI) in fecal samples, and that the OR risk in both tissue and fecal samples increased significantly to 70.35 and 30.10 from precancerous disease (adenoma or polyp) to CRC. There were significant differences between tissue and fecal hypermethylation frequency. On the basis of the hypermethylation frequency of colorectal tissue, the coincidence rates of fecal hypermethylation in CRC and colorectal adenoma were 0.89 and 0.9, respectively. The risk size of SFRP2 hypermethylation from normal control to adenoma or polyp as well as from adenoma or polyp to CRC increased gradually in both tissue and feces. Therefore, SFRP2 hypermethylation is an important biomarker both in noninvasive diagnosis in feces detection and in colon tissue.