To study the analysis of SEPT9 gene methylation in diagnosis and follow-up of colorectal cancer.

The clinical data of 783 cases of colorectal cancer screening in our hospital from October 2014 to December 2015 were analyzed. There were 72 patients diagnosed with colorectal cancer, 711 cases were excluded colorectal cancer. In there, all patients were performed by peripheral blood SEPT9 methylation detection and pathological examination. Pathological diagnosis was used as gold standard, with the ROC curve, the diagnostic value of SEPT9 positive for colorectal cancer was evaluated. After 1 years of follow-up, the SEPT9 gene methylation and the survival of the patients were observed. Statistical analysis were performed by using SPSS 23.0 software, the classification data such as sex, age, location of lesion, TNM stage and et al were presented as n(%), and examined by using Chi square test. A P<0.05 was considered as significant difference.

The level of SEPT9 gene methylation of colorectal cancer patients was significant higher than non-colorectal cancer patients. The positive rate of SEPT9 gene methylation of colorectal cancer patients in stage Ⅰ, stage Ⅱ, stage Ⅲ and Ⅳ was 47.4%, 69.2%, 88.89%, 88.9% respectivly. ROC curve analysis showed that the SEPT9 was higher than that of CA125 and CA199 curve (P<0.05), the sensitivity and specificity of the diagnosis of colorectal cancer was 86.5% and 70.8%. After 1 year of follow-up, 88.2% of positive SEPT9 gene methylation patients turned to negative after colorectal cancer surgery, compared with this patients, the prognosis of patients whose SEPT9 methylation had not turned to negative had a poor prognosis.

SEPT9 gene methylation could be used as an important test indicator for the risk and prognosis of colorectal cancer.