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.

Transcriptional inactivation of ERbeta gene is mediated by the induction of promoter hypermethylation in a rat colonic epithelial cell model.

BACKGROUND: To construct a primary rat colonic epithelial cell model for treatment with specific methylated oligonucleotides (MOs) and to determine whether the transcriptional inactivation of ERbeta mRNA is mediated by the induction of hypermethylation of the ERbeta gene promoter. METHODS: Suckling rat colonic epithelial cells were cultured in DMEM. Two methylated oligonucleotides complementary to the promoter regions of ERbeta were synthesized and applied to the cultured cells to induce promoter hypermethylation of the ERbeta gene. Methylation-specific PCR (MSP) was used to determine the methylation status of the ERbeta promoter in the cultured cells. Reverse transcription-polymerase chain reaction (RT-PCR) was used to quantify the expression of ERbeta mRNA after treatment with MOs. RESULTS: Suckling rat colonic epithelial cells were successfully cultured in vitro. The MOs and unmethylated oligonucleotides (UMOs) we designed, synthesized, successfully transfected into the colonic epithelial cells, and assembled in the nuclei of the cells, which had extremely elevated proliferative activity. RT-PCR demonstrated that the expression of ERbeta mRNA was significantly suppressed in the cells treated with MOs, whereas its expression in the control cells treated with UMOs was not. MSP analysis showed that the promoter of ERbeta in the cells treated with MOs was hypermethylated compared with that of the control cells. CONCLUSION: The transcriptional inactivation of ERbeta mRNA in rat colonic epithelial cells may be mediated by the hypermethylation of the ERbeta gene promoter. Our model markedly simulates the epigenetic modification of the ERbeta gene in colonic cancer cells.