Clinical significance of plasma methylated SEPT9 gene test for colorectal cancer / 中华检验医学杂志

ABSTRACT

Objective To investigate the clinical significance of plasma methylated Septin 9 (SEPT9)gene test for colorectal cancer(CRC).Methods Clinical data of this retrospective study were obtained from Huashan Hospital of Fudan University(2016-2017).The subjects were divided into three groups,84 patients in CRC group,50 patients with adenoma in precancerous group,and 20 cases as healthy controls.A fluorescent PCR assay was used to analyze SEPT 9 methylation in DNA extracted from plasma. Chi square test was used for statistical analysis.Results The positive incidence of SEPT9 gene methylation in plasma was 63.1%(53/84)in CRC group,significantly higher than 10%(5/50)in precancerous group (χ2=35.993, P<0.001), and undetectable in healthy group.The sensitivity of the methylated SEPT9 gene test was 63.1%(53/84), and the sensitivity of a joint detection combined with carcinoembryonic antigen(CEA)was 75%(63/84).The receiver operating characteristic curve(ROC)showed that methylated SEPT9 gene test had 0.828 in the area under the curve(AUC),higher than 0.795 in the AUC of CEA test.In CRC patients,51.4%(19/37)in the stage Ⅰ-Ⅱand 72.3%(34/47)in the stage Ⅲ-Ⅳ were positive for methylated SEPT9 gene test(χ2=3.917, P<0.05).There were no significant differences in gender,age and primary tumor site.Conclusion The SEPT9 gene methylation in plasma is helpful for early screening for CRC,and is associated with CRC progression.