Comparative detection of syndecan-2 methylation in preoperative and postoperative stool DNA in patients with colorectal cancer

Figure 1  Flowchart of preoperative and postoperative sample collection in patients with colorectal cancer.

Figure 2 Percentages of syndecan-2 methylation test results according to tumor node metastasis stage. Using the 1/2 algorithm, the percentage of samples with detectable methylated syndecan-2 is presented by bars. A: Preoperative stool samples were collected from 123 patients. Overall sensitivity was 88.6%; B: Postoperative stool samples were collected from 122 patients. Overall specificity was 80.3%. SDC2: Syndecan-2; TNM: Tumor node metastasis.

Figure 3 Distribution of syndecan-2 methylation according to tumor node metastasis stage. The cycle threshold (C_T) values for each sample were calculated as 40-C_T. A higher 40-C_T indicates a higher methylation level of syndecan-2 (SDC2). If SDC2 methylation was not detected, it was expressed as 0. A: Preoperative (n = 123); B: Postoperative (n = 122). SDC2: Syndecan-2; C_T: Cycle threshold; TNM: Tumor node metastasis.

Figure 4 Paired cycle threshold values of syndecan-2 methylation before and after surgery for each patient (n = 104). The cycle threshold (C_T) values were calculated as 40-C_T. A higher 40-C_T indicated a higher methylation level of syndecan-2 (SDC2). If SDC2 methylation was not detected, it was expressed as 0. P value was calculated using a paired t-test. SDC2: Syndecan-2; C_T: Cycle threshold.