Screening And Identification Of Colorectal Cancer And Adenomatous Polyps Using MNP-RT-PCR Method

Objective:To explore the feasibility of MNP-RT-PCR in fecal screening of colorectal cancer and adenomatous polyps,comparing with fecal occult blood tests of screening.At the same time,we try to use MNP-RT-PCR technique to detect the COX-2expression of the samples with colonoscopic brush,and explore the feasibility of identification among colorectal cancer,adenomatous polyps and normal mucosa with this technique.Methods:1.Collect500cases of high-risk patients at Tianjin Union Medical Center in June-December of2012,to be identified by the next colonoscopic biopsy for diagnosis,including13cases with colorectal cancer,34cases with adenomatous polyps,and453cases with other patients.Other patients include397cases with normal colorectal mucosa,the rest includes inflammatory bowel disease.inflammatory polyps,melanosis and so on.2. Take a small amount of feces(approximately1g) of500patients,use MNP to extract the total RNA of the feces,and then use RT-PCR to amplify COX-2. Use the Ct value relative quantification analysis,to compare expression difference among each group indirectly by comparing2-△△Ct value of the group. With the statistical software of SPSS17.0,make ROC curve analysis for the result,plot the ROC curve and calculate the area under the curve,take the best screening critical point by the sensitivity+specificity is the highest.Then we can determine the sensitivity and specificity of MNP-RT-PCR method. At the same time use colloidal gold fecal occult blood test to screen this500cases of high-risk patients,and calculate the sensitivity and specificity of this method.Compare the sensitivity and specificity of two methods.3.Collect444patients of above cases(13cases with colorectal cancer,34cases with adenomatous polyps,and269cases with normal mucosa),brush lesions(colorectal cancer and adenomatous polyps) or normal parts(normal mucosa) under colonoscopy,then use MNP-RT-PCR to detect the expression of COX-2,and compare the difference of COX-2expression among three groups.Results: 1.With the detection of COX-2expression for500cases by MNP-RT-PCR,COX-2expression of the colorectal cancer group was significantly higher than that of the adenomatous polyps group and the other group(p<0.05),COX-2expression of the adenomatous polyps group was significantly higher than that of the other group(p<0.05).2.For the screening of colorectal cancer by MNP-RT-PCR,the sensitivity is76.9%,the specificity is74.5%;for the screening of adenomatous polyps by MNP-RT-PCR,the sensitivity is70.6%,the specificity is76.0%.For the screening of colorectal cancer by fecal occult blood test,the sensitivity is61.5%,the specificity is64.1%;for the screening of adenomatous polyps by fecal occult blood test,the sensitivity is41.2%,the specificity is63.7%.3.For the sample detection of colonoscopic brushing by MNP-RT-PCR.COX-2expression of the colorectal cancer group was significantly higher than that of the adenomatous polyps group and normal colorectal mucosa group(p<0.05),COX-2expression of the adenomatous polyps group was significantly higher than that of colorectal normal mucosa group(p<0.05).Conclusion:1. MNP is an effective extraction technology,with high purity.good quality,simple operation,and brief workflow.The sensitivity of RT-PCR is high,and the combination of two parts makes extraction efficiency of nucleic acid improved greatly.2.For the stool screening of colorectal cancer and adenomatous polyps,the sensitivity and specificity of MNP-RT-PCR is higher than fecal occult blood test,and MNP-RT-PCR is effective for the screening of colorectal cancer and adenomatous polyps.MNP-RT-PCR requires smaller amount of samples,while fecal occult blood test is more simple and costs lower.3.MNP-RT-PCR identified colorectal cancer,adenomatous polyps and normal colorectal mucosa by detecting COX-2levels,and found that the COX-2expression of colorectal cancer group was significantly higher than the group of adenomatous polyps and normal colorectal mucosa,and the COX-2expression of adenomatous polyps was significantly higher than normal colorectal mucosa.MNP-RT-PCR technique can be used to identify colorectal cancer, adenomatous polyps and normal colon mucosa.4.COX-2levels showed a decreasing relationship among colorectal cancer,adenomatous polyps and normal colorectal mucosa,and they exist some some causal link in happening and development.5.COX-2expression in tissues has no correlation with gender,age and other factors.6. Under the premise of no damage to lesions by colonoscopy,brushing cytology is an very effective way to draw,preventing bleeding after taking the biopsy by forceps,but they are faced with colonoscopy,and some people will feel pain.7.Currently pathological examination is still the gold standard for diagnosis irreplaceably,but this examination is cumbersome and time-consuming,and there are some deficiencies which should be improved.