Abstract:

Objective

To investigate the construction and validation of a model for prediction of colorectal cancer （CRC） by circulating tumor DNA （ctDNA） methylation.

Methods

Prospectively enrolled colorectal cancer patients between August 2021 and July 2023 were selected as the study subjects（CRC group），and age-and gender-matched healthy medical check-ups in the same period served as the control group. The two groups were compared in terms of clinical data and serum ctDNA methylation levels； DNA methylation markers of CRC were obtained from the public database “Marmal-aid”； DNA methylation markers were screened by LASSO and RF analyses. The model of CRC prediction based on the screened DNA methylation markers was constructed by ROC curve and logistic multifactorial regression analysis； the prediction efficacy of the model for CRC was clarified by the training cohort and validation cohort，respectively.

Results

A total of 3997 differentially DNA methylated CpGs （DMCs）were identified by screening through public databases，and 19 methylation markers were retained by stepwise screening through hierarchical clustering and KEGG showing the different methylation patterns and enrichment pathways between CRC and normal colorectal mucosa in these DMCs. The stability of the 19 markers was assessed by LASSO and RF analyses，and three DNA methylation markers （cg08131100，cg16934178，and cg24171907） were obtained，with predicted AUCs of 0.887，0.841，and 0.715 for CRC，respectively. Logistic regression analyses showed that cg08131100，cg16934178 and cg24171907 were independent risk factors influencing the onset of CRC； the methylation scores of CRC were significantly higher than those of the control group in both the training and validation cohorts； and the efficacy of the methylation model in predicting CRC was evaluated by ROC curves，and the model had an AUC of 0.841 in the training group （95% CI： 0.756-0.927），and the AUC of the model in the validation group was 0.823 （95%CI： 0.728-0.919）.

Conclusion

This study constructs a model for prediction of CRC patients based on ctDNA methylation，which provides a clinically translatable tool for noninvasive detection and screening of CRC.

Key words: Colorectal cancer, Circulating tumor DNA, Methylation, Prediction model