Significance Of MiR-92a In Stool Samples As Screenlng Biomarkers For Colorectal Cancer And Polyps

Background and Objective:Fecal occult blood testis the main technique for colorectal cancer screening with the sensitivity of only50-60%, especially lower for adenomas (-30%)[1], and therefore a non-invasive method for colorectal cancer screening with a higher sensitivity is expected. Previous studies have found that the expression of miRNA-92a is significantly different in dry stool between clinical patients with colorectal cancer, colorectal adenoma and control. However, there is no study which detects miRNA-92a expression levels in dissolved stool samples from screening field. Stool samples from screening field were dissolved in hemoglobin preservation solution. If miRNA-92a can be detected from dissolved stool samples, it will greatly simplify the sample collection process.Materials and Methods:In this study, nested case-control samples is formed from colorectal cancer population screening in Jiashan which collects adenoma patients and normal controls dissolved stool samples, combined with clinical dry samples of colorectal cancer patients. Using colonoscopy and pathology diagnosis as gold standards, stool samples from screening was used to verify the relationship between the expression of miRNA-92a and colorectal tumor. The diagnostic value of miRNA-92a combined fecal occult blood test in screening for colorectal cancer is analyzed. This study collected41clinical patients with colorectal cancer,42patients with polyps and43normal controls from screening field. MiRNA in stool samples are purified by centrifugation and filtration. The expression of miR-92a is detected by fluorescence quantitative PCR with miRNA U6as a reference gene.Results:(1) The expression of miRNA-92a in clinical stool samples of colorectal cancer patients is significantly higher than dissolved stool samples in normal controls from screening field (p<.05). The expression ofmiRNA-92a in dissolved stool samples from adenoma patients is significantly higher than dissolved stool samples in normal controls (p<.05).(2) When the cutoff value is0.07413, the sensitivity of miR-92a expression for colorectal cancer screening is87.8%(73.80%-95.92%),sensitivity of miR-92a expression for colorectal polys screeing is52.4%(95%Cl:36.28%-68.23%) and the specificity is48.8%(33.31%-64.54%).(3) Fecal miR-92a and OB in parallel improve the sensitivity for the diagnosis of colorectal cancer, increased to95.1%(95.03%-95.16%), rising by69.5%compared with only FOBT. Fecal miR-92a and OB in parallel improve the sensitivity for the diagnosis of colorectal polys, increased to57.1(57.02%-57.18%), rising by three times compared with only FOBT.Conclusion:The expression of miRNA-92ais obviously different between dry stool from clinical patients with colorectal cancer, dissolved stool from adenoma patients and normal controls from screening field. MiRNA-92a have potential to be a molecular marker in screening of colorectal cancer and adenoma. When miRNA-92a is used in clinical, different cut-off value can be select with different sensitivity and specificity. MiR-92a and fecal occult blood test combined in parallel can increase screening sensitivity. Further large cohort studies are still needed to certify miR-92a as an effective molecular marker in colorectal cancer screening and feasibility of stool dissolved in hemoglobin preservation solution...