Diagnosticvalue Of Combined Detection Of Serum Circulating Free DNA And CEA For Colorectal Cancer

0bjective:In this study,the purpose of this study was to investigate the value of circulatingcell-free DNA(cf DNA)and CEA in the diagnosis of colorectal cancer.To study the diagnostic value of cf DNA content,CEA content and combined detection for colorectal cancer,and to find indicators with high sensitivity and specificity.Method: This study adopted a case-control approach.A total of 30 hospitalized patients with colorectal cancer and benign colorectal disease treated in the Department of General Surgery,Anorectal,and Gastroenterology of the Affiliated Hospital of Beihua University from July 2019 to December 2019 were collected.The control group chose to collect a total of 30 healthy patients during the same period example.All patients were diagnosed clearly by colonoscopy and pathology,meeting the inclusion criteria.First,the serum cf DNA of all subjects was extracted and stored at-80℃.Genomic DNA of healthy human blood was extracted and diluted into 5 concentration gradients as standard.The serum cfDNA and standard DNA of all the research subjects were subjected to fluorescent quantitative PCR using ALU-115 fragment as a primer.The ct value obtained during the fluorescence PCR process of the standard was used to establish a serum cf DNA concentration standard curve to obtain the research subject cf DNA concentration.CEA content in serum of all subjects was detected by ADVIA Cenurcpchemiluminescence analyzer.Compare the cf DNA content and CEA content of colorectal cancer group,benign colorectal disease group and healthy physical examination group,analyze the relationship between colorectal cancer cf DNA content,CEA content and clinical pathological parameters of colorectal cancer,and explore serum cf DNA content The diagnostic value of CEA content in colorectal cancer.ROC curves were drawn separately for sensitivity and specificity analysis of single indicator and combined test results.Results:1.Draw the standard concentration curve of cf DNA.2.Cf DNA content and CEA content of each group were obtained In the colorectal cancer group,the median cf DNA content(interquartile spacing)was 52.7085ng/ml(iqr15.0338-80.5740)ng/ml,and the median CEA content(interquartile spacing)was 4.72ng/ml(iqr2.12-7.90)ng/ml.In the colorectal benign disease group,the median cf DNA content(interquartile spacing)was 23.6214ng/ml(iqr19.6724-27.8256)ng/ml,and the median CEA content(interquartile spacing)was 2.04ng/ml(iqr1.45-2.78)ng/ml.In the health and physical examination group,the median cf DNA content(quartile spacing)was 7.1750ng/ml(iqr5.2265-9.4152)ng/ml,and the median CEA content(quartile spacing)was 1.16ng/ml(iqr0.84-1.95)ng/ml.The median cf DNA content and CEA content of colorectal cancer were statistically different from those of benign colorectal disease group and healthy group.The median cf DNA and CEA content of colorectal benign disease group and healthy group were statistically different.3.Correlation between cf DNA content and CEA content and clinical pathological parameters in colorectal cancer patients There was no significant correlation between cf DNA content and gender,age,smoking status,and distant metastasis of colon cancer patients,and there was a significant correlation between cf DNA content and the degree of differentiation of colon cancer patients(P <0.05).There was no significant correlation between serum CEA levels and gender,age,smoking status,clinical stage,and degree of differentiation in patients with colorectal cancer.4.Value of serum cf DNA content and CEA content in the diagnosis of colorectal cancer The ROC curve was drawn according to the serum cf DNA content and CEA content of the colorectal cancer group.The area between the curve and the X coordinate represents the value of this indicator in the diagnosis of colorectal cancer.The area under the ROC curve of cf DNA content and CEA content were measured respectively: 0.828 and 0.853.When the cf DNA fragment content reached 32.588 ng / ml,the sensitivity was 66.7%,the specificity was 96.7%,and the CEA fragment content reached 3.230 ng./ ml,with a sensitivity of 73.3% and a specificity of95.0%.The area under the ROC curve of the combined detection of cf DNA content and CEA content can reach 0.898.The combined sensitivity is 76.7% and specificity is 98.9%.Conclusion:1.Cf DNA content and CEA content were significantly increased in the serum of colorectal cancer patients,indicating that cf DNA content and CEA content were expected to become tumor markers for the diagnosis of colorectal cancer.2.The combined detection of cf DNA content and CEA for the diagnosis of colorectal cancer is more sensitive and specific than the single test.The combined detection is helpful to improve the diagnosis rate of colorectal cancer.