Stool DNA test of methylated syndecan-2 for the early detection of colorectal neoplasia

Background: Although the incidence of colorectal cancer is steadily increasing, screening for colorectal cancer with conventional approaches is not routinely performed in China. Noninvasive screening methods are attractive options to resolve this issue. Syndecan-2 (SDC2) is frequently methylated in colorectal cancer. However, the value of a stool test of methylated SDC2 for the detection of colorectal cancer is unknown. Methods: Methylation status of SDC2 was tested in cell lines and 398 colorectal tissue samples and further evaluated with 497 stool samples, including 196 from colorectal cancer patients, 122 from adenoma patients, and 179 from normal individuals, using real-Time methylation-specific PCR. The impacts of one quantitative partial stool sampling device and 17 potentially interfering substances on the performance of fecal methylated SDC2 were also analyzed. SDC2 expression was also measured. Results: SDC2 methylation level was higher in 96.8% (120/ 124) of colorectal cancer tissues compared with paired adjacent normal epithelia. Stool test of methylated SDC2 detected 81.1% (159/196) of colorectal cancer and 58.2% (71/122) of adenomas at a specificity of 93.3% (167/179). No significant difference was found between partial and whole stool collection on colorectal cancer detection (P > 0.05, R2 = 0.80). Among 17 interfering substances, only berberine at high concentrations inhibited fecal detection of methylated SDC2. SDC2 was overexpressed in colorectal cancer tissues compared with normal epithelia. Conclusions: Fecal methylated SDC2 is a valuable biomarker for the noninvasive detection of colorectal neoplasms. Impact: Stool DNA test of methylated SDC2 would serve as an alternative method for screening colorectal neoplasms.