Abstract
The aim of the present study was to examine the diagnosis of methylation of CDX2 gene promoter in colorectal cancer (CRC) and assessed its value in the prediction of treatment efficacy. Sixty patients who were diagnosed as CRCs for the first time, 60 patients with hyperplastic polyps (HPs) and adenomas, and 60 patients with inflammatory lesions or healthy patients (control group) were included in the present study. The methylation levels of CDX2 gene promoter were detected by methylation-specific polymerase chain reaction (MSP), and the expression levels of CDX2 mRNA were detected by fluorescence quantitative PCR. Treatment options, such as surgery, radiotherapy and chemotherapy, were chosen on the basis of TNM staging of CRC patients. The tumor-free survival, relapse rate and mortality were also recorded. The methylation rate was 71.67% (43/60) and significantly higher in the CRC group as compared to the HP/adenoma and control groups, P<0.05. Moreover, they showed further increase with higher degree of TNM staging. The expression levels of CDX2 mRNA was significantly lower in the CRC group in comparison to HP/adenoma and control groups, P<0.05, and showed a further decrease with a higher degree of TNM staging. The tumor-free survival was shorter, and the relapse rate and mortality were higher in patients with positive methylation in the CRC group, P<0.05. Multivariate logistic regression analysis demonstrated that TNM staging and positive methylation were independent risk factors of mortality. In conclusion, higher methylation degree of CDX2 gene promoter resulted in decreased expression of CDX2 gene, and was closely associated with TNM staging and prognosis. TNM staging and positive methylation were independent risk factors of mortality for CRC patients.