[Screening and diagnostic value of the molecular markers of DNA methylation in colorectal neoplasma].

Objective: To screen the molecular markers of DNA methylation with potential diagnostic value, and to explore their methylation features in Chinese colorectal neoplasma in order to find out ones with higher diagnostic value.
Methods: Tissue samples of colorectal cancer and normal adjacent mucosa(>10 cm distance to tumors) from 10 colorectal cancer patients undergoing operation, and tissue samples of colorectal adenoma from 10 patients undergoing endoscopic resection in our center from June to August 2013 were collected respectively. Methylation status of 8 genes, such as SNCA, MAL, INA, SPG20, FBN1, CNRIP1, TFPI2, OSMR, was detected by BSP and qMSP to screen genes with potential diagnostic valua. ROC curve was drawn to analyze its diagnostic value.
Results: BSP measurement showed that the rate of DNA methylation of SNCA, SPG20 and FBN1 was 100% in colorectal cancer and adenoma, while no methylation was found in normal adjacent mucosa. The other 5 genes expressed in different extent in cancer, adenoma and normal adjacent mucosa. Among 10 cancer tissues and normal adjacent mucosa detected by qMSP method, positive SNCA methylation was found in 5 cases and 1 case respectively; positive SPG20 in 8 cases and 1 case respectively; positive FBN1 in 7 cases and 0 cases respectively, whose differences were significant (P=0.070, P=0.003 and P=0.007). The area under curve(AUC) of SNCA, SPG20, and FBN1 methylation for diagnosing colorectal cancer was 0.890, 0.730 and 0.880 respectively.
Conclusion: SNCA, SPG20 and FBN1 are potential genes with screening value for colorectal neoplasma.