Early colorectal cancer diagnosis: A novel methylated stool DNA model enhanced the diagnostic efficiency.

Background: Methylated stool DNA (sDNA) is a reliable noninvasive biomarker for early colorectal cancer (CRC) diagnosis. However, there are barely any diagnostic panels that can achieve both a sensitivity and specificity exceeding 90% simultaneously.

Objective: We aimed to identify a novel methylated sDNA panel and model for the early diagnosis of CRC.

Methods: We conducted methyl-CpG binding domain isolated genome sequencing (MiGS) on CpG island methylation phenotype (CIMP)-positive (n = 3) and CIMP-negative CRC tissues (n = 3) and their corresponding normal adjacent tissues. Subsequently, by utilizing both the aforementioned data and public datasets, we identified a set of promising methylated sDNA markers for CRC. Next, we validated 5 of these genes using pyrosequencing in CRC patients (n = 31). Then, we developed a combined diagnostic model (CDM) for CRC based on the methylation status of PRDM12, FOXE1, and SDC2 by a Training cohort (n = 231). Finally, the performance of CDM was evaluated in an independent multicenter Validation cohort (n = 800).

Results: A total of 1062 participants were included in this study. The area under the curve (AUC) of the CDM was 0.979 (95% CI: 0.960-0.997), and the optimal sensitivity and specificity were 97.35% and 99.05%, respectively, in the training cohort (n = 231). In the independent validation cohort (n = 800), the AUC was 0.950 (95% CI: 0.927-0.973), along with the optimal sensitivity of 92.75% and specificity of 97.21%. When CRC and advanced adenoma (AAD) were used as diagnostic targets, the model AUC was 0.945 (95% CI: 0.922-0.969), with an optimal sensitivity of 91.89% and a specificity of 95.21%. The model sensitivity for nonadvanced adenoma patients was 68.66%.

Conclusion: The sDNA diagnostic model CDM, developed from both CIMP-P and CIMP-N, exhibited exceptional performance in CRC and could serve as a potential alternative strategy for CRC screening.