High methylation of the SEPT9 gene in Chinese colorectal cancer patients.

Methylation of the septin 9 gene (SEPT9) occurs in higher frequency in colorectal cancer (CRC) compared to control samples, which suggests that SEPT9 methylation is a useful biomarker for screening CRC. However, the methylation status of SEPT9 in Chinese CRC patients is scarcely reported. In the present study, SEPT9 methylation was tested in CRC tissues obtained from a Chinese population and correlations with pathological characteristics were investigated. The methylation status of SEPT9 was detected using methylation-specific polymerase chain reaction (PCR)-denaturing high-performance liquid chromatography (MSP-DHPLC) in 234 colorectal tissues (172 cases, 62 controls). Samples were sequenced to confirm the results from MSP-DHPLC. The chi-squared test was used to analyze the correlation of SEPT9 gene methylation status and pathological characteristics in CRCs. SEPT9 gene methylation was detected in 152 of 172 (88.4%) cases of verified CRC and in 4 of 62 (6.5%) healthy controls (χ(2) = 137.62, P < 0.001). There was no association between the methylation status of SEPT9 and age, gender, Duke's stage, TNM stage, differentiation, and site of cancer (P > 0.05). Our results suggest that SEPT9 gene methylation is a valuable biomarker for screening CRC in the Chinese population.