Combined Detection On Gene Methylation Of Septin 9 And Vimentin In Feces For Colorectal Cancer Screening

Objective:This study is to explore the gene methylation of Septin 9 (SEPT9) and Vimentin (VIM) in feces for colorectal cancer (CRC) and to analyze the sensitivity and specificity in CRC diagnosis.Methods:We collected feces of CRC patients, colorectal polyp patients and healthy controls treated in the Fourth Affiliated Hospital of Guangxi Medical University from December 1st,2014 to March,31st,2016. All the samples were taken prior to endoscopic therapy, surgery, radiotherapy and chemotherapy. DNA extraction kits were employed to extract genomic DNA from feces and then Methylation Special Polymerase (MSP) chain reaction was applied to test gene methylation of SEPT9 and VIM for each fece. Finally, SPSS statistic software were used to analyze its sensitivity and specificity in CRC diagnosis.Results:1. In CRC patient group, detectable rates of SEPT9 or VIM alone were 72.7%(32/44) and 68.2%(30/44) respectively while the rate of combined detection on both genes was 93.2%(41/44). In colorectal polyp patient group, the rate were 32.5%(13/40),22.5%(9/40) and 35.0%(14/40) respectively.In healthy control group, the rates were 8.1%(3/37),5.4%(2/37), and 8.1%(3/37) respectively; 2. Sensitivities of SEPT9 detection, VIM detection and combined detection of two genes for CRC diagnosis were 72.7%(32/44),68.2%(30/44) and 93.2%(41/44) respectively, with statistical significance(.P=0.000), which indicated that the combined detection on both genes was more sensitive than that on SEPT9 or VIM alone with statistical significance(P=0.011 and P=0.003 separately). Respective specificity for the three detection approach was 79.2%(61/77),85.7%(66/77) and 77.9%(60/77) with no statistical significance (P=0.344); 3. SEPT9’s detection rates for CRC Ⅰ-Ⅱ and CRC Ⅲ-Ⅳ were 65.0%(13/20) and 79.2%(19/24) respectively whereas VIM’s detection rates for CRC Ⅰ-Ⅱand CRC Ⅲ-Ⅳ were 60.0%(12/20) and 75.0%(18/24) respectively. Combined detection rates for CRC Ⅰ-Ⅱ and CRC Ⅲ-Ⅳ were 90.0%(18/20) and 95.8%(23/24), (all P>0.05), with statistical significance.Conclusion:Combined detection, tested by MSP method, on gene methylation of SEPT9 and VIM in feces might be an noninvasive, convenient, economic, effective technique for CRC screening due to its high detectable rate, sensitivity and specificity.