Combined Detection Of Fecal Genes SDC2 And BMP3 In Colorectal Cancer Screening

BackgroundIn China,colorectal cancer(CRC)is one of the most common malignant tumors.The incidence and mortality of CRC rank third and fifth in malignant tumors,respectively.It is urgently needed to take effective measures(such as CRC screening)to control the high incidence of CRC.At present,colonoscopy is the gold standard for CRC screening,but colonoscopy requires bowel preparation,has the risks of bleeding and perforation,and has a painful examination procedures,which result in low compliance for colonoscopy in average-risk groups of CRC.Nowadays,simplicity,non-invasiveness,high diagnostic performance,and high compliance have become important issues for CRC screening.With the in-depth study of CRC,epigenetics,especially DNA methylation,has shown an increasingly vital role in the occurrence and development of CRC.Using bioinformatics and molecular biology techniques,it has been found some DNA methylation is suitable for screening,diagnosis,treatment and prognosis of CRC.ObjectiveTo investigate the diagnostic performance of stool gene SDC2 methylation and BMP3 methylation in CRC and adenoma,and to investigate whether the combined detection of two genes is better than the single gene detection.MethodsFecal samples were collected from 64 patients who underwent colonoscopy or underwent surgery for CRC at Guangzhou Twelfth People's Hospital Affiliated to Guangzhou Medical University and Sun Yat-sen University Cancer Center between May 2019 and September 2019,including 29 patients with CRC,9 patients with adenoma disease,and 26 patients without CRC or adenoma diseases.Fecal DNA was extracted,then bisulfite modified,and the fecal gene SDC2 and BMP3 methylation status was detected in three groups using methylation-specific PCR(MSP).Compared with single gene SDC2 or BMP3 methylation detection,we calculated the sensitivity and specificity of combined detection of stool gene SDC2 and BMP3 in CRC group and adenoma group.Results1.The positive rates of methylation of SDC2 and BMP3 genes in CRC patients were 65.5%(19/29)and 44.8%(13/29),respectively,which were significantly higher than those in control group 15.4%(4/26)and 7.7 %(2/26),and the differences were statistically significant(P <0.05).2.The sensitivity of combined detection for CRC was higher than that of BMP3 gene detection(82.8% vs 44.8%),and the differences was statistically significant(P <0.01);also was higher than that of SDC2 gene detection(82.8% vs 65.5%),with no statistically significant difference(P > 0.05).Compared with SDC2 gene detection or BMP3 gene detection,the sensitivity of combined detection in adenoma was not statistically significant difference(P > 0.05).The specificity of the combined detection for CRC or adenoma was lower than that of SDC2 gene detection(80.8% vs 84.6%)or BMP3 gene detection(80.8% vs 92.3%),with no statistically significant differences(P > 0.05).3.SDC2 gene detection,BMP3 gene detection and combined detection showed no statistically significant difference in detection rate between different ages,genders,tumor size,stage,and differentiation(P > 0.05).BMP3 gene detection and combined detection found more distal CRC(P < 0.05),while SDC2 gene detection has no statistically significant difference in the detection rate of proximal or distal tumors(P > 0.05).Conclusion1.SDC2 gene detection and BMP3 gene detection using MSP method could distinguish CRC patients and control group patients,which were a potential ideal CRC screening method.2.The diagnostic performance of combined detection of CRC was superior than those of BMP3 methylation detection,but there was no significant improvement compared with SDC2 methylation detection;the combined detection of stool gene needs to be optimized.