DNA Methylation Profile in Buffy Coat Identifies Methylation Differences Between Cirrhosis with and Without Hepatocellular Carcinoma

Background: / Objectives: Cirrhosis is the precursor to most cases of hepatocellular carcinoma (HCC). Understanding the mechanisms leading to the transition from cirrhosis to HCC and identifying key biomarkers is crucial to developing effective screening strategies and reducing HCC-related mortality. DNA methylation is associated with gene inactivation and plays an important role in physiological and pathological processes; however, its role in cirrhosis progression to HCC is unknown. Methods: We performed genome-wide DNA methylation profiling using Illumina Infinium MethylationEPI BeadChip, in pre-diagnostic samples from 22 cirrhosis patients who subsequently developed HCC and 22 cirrhosis patients who remained HCCfree during an average 4-year follow-up. In a secondary analysis, we examined a subset of patients without hepatitis C virus (HCV) infection. Results: We identified three differentially methylated positions (DMPs) located in ADAM12 (cg13674437) and PSD3 (cg06758847 and cg24595678) that show a strong association with HCC risk (lower median vs. higher median hazards ratio (HR): HR cg13674437=0.34, 95% CI=0.14 – 0.83; HR cg06758847=4.89, 95% CI=1.79 – 13.33; HR cg24595678=11.19, 95% CI=3.27 – 38.35). After excluding all HCV-active patients from our analysis, HR for the DMPs remained as significant. Conclusions: In conclusion, the findings in this study support that buffy coat-derived DNA methylation markers could be used to identify biomarkers among cirrhosis patients at high risk for HCC before clinical symptoms appear. A further multi-omics study with a large prospective cohort is required to validate these findings.