Background Endometrial cancer (EC) is a common malignant gynecological tumor with a rising incidence globally. This study aimed to integrate DNA methylation analysis of cervical scrapings with transvaginal ultrasound (TVUS) imaging to develop a more effective non-invasive diagnostic strategy for EC. Methods Methylated cytosine-guanine dinucleotide (CpG) tandem amplification and sequencing was used for genome-wide methylation profiling on EC tissues, adjacent normal tissues, and cervical scrapings from 20 EC patients and 20 benign endometrial thickening controls. Samples were randomly divided training and validation cohorts at a ratio of 6:4. Sequencing depth was 30× with coverage ≥90%, and repeatability was validated (intraclass correlation coefficient ≥0.85). BWA-Meth was used for alignment and the β-value method for methylation level calculation. Strict quality control was applied (DNA concentration ≥20 ng/μL, OD260/280 = 1.8~2.0) with preset sample criteria (≥5000 cells, ≥40% cell proportion, ≥20 mg weight). TVUS parameters were correlated with methylation findings. Four diagnostic strategies were evaluated: methylation biomarkers alone, TVUS alone, direct combination, and sequential approach (TVUS followed by methylation testing). Results Significant differences were observed in Adler blood flow grade and endometrial-myometrial border irregularity between EC and control groups ( P 0.05). Methylation analysis identified 2,671 differentially methylated CpG sites corresponding to 745 differentially methylated genes (DMGs). Three core methylation biomarkers (BAHCC1-8721-2-1, SHANK3-16286-1-5, FHL1-26624-1-3) were screened in the training set, with single-gene area under the curve (AUC) of 0.804, 0.782, and 0.844, respectively. Combined methylation biomarkers achieved an AUC of 0.922 (sensitivity 85.0%, specificity 90.0%). TVUS alone had an AUC of 0.725; direct combination yielded an AUC of 0.900. The sequential approach showed the highest performance with an AUC of 0.950 (sensitivity 90.0%, specificity 95.0%). Delong test confirmed significant differences between the sequential strategy and TVUS alone or direct combination ( P 0.05). Conclusion Cervical scraping-based methylation analysis may serve a useful non-invasive tool for EC detection. The sequential combination of TVUS and methylation testing appears to improve diagnostic accuracy, suggesting a potential strategy for early EC screening. This is a single-center exploratory study with a small sample size, and the results need to be validated in large-scale, multi-center independent cohorts.
Liu et al. (Wed,) studied this question.