Abstract LB103: Cell-free DNA methylation as a noninvasive prognostic biomarker in hepatocellular carcinoma
Authors: Hu Ran , Tran Benjamin , Li Shuo , Stackpole Mary L. , Zeng Weihua , Zhou Yonggang , Melehy Andrew , Zhou Xianghong , Li Wenyuan , Agopian Vatche 
Published: April 2024

Abstract
The current noninvasive prognostic evaluation of hepatocellular carcinoma (HCC) using markers such as imaging features and serum biomarkers like alpha-fetoprotein (AFP) is limited due to low sensitivity. Pathologic tumor features can enhance prognosis beyond imaging and AFP, yet pre-surgical percutaneous biopsies are invasive, not routinely pursued, and may not be representative of the entire tumor. There is a critical unmet need to develop noninvasive blood-based HCC biomarkers to guide therapeutic decisions. Epigenetic changes in circulating cell-free DNA (cfDNA) have shown promise in early cancer diagnosis and prognosis. Therefore, we aim to evaluate the potential of cfDNA methylation as a noninvasive predictor for pre-treatment prognostication in HCC patients. Using Illumina HumanMethylation450 array data of 377 HCC tumors and 50 adjacent normal tissues obtained from The Cancer Genome Atlas (TCGA), we systematically identified 158 HCC-related DNA methylation markers associated with overall survival (OS). Functional analyses of these markers indicated their roles in regulating gene expression and revealed biological pathways associated with HCC patient survival. We predicted an OS risk score utilizing the DNA methylation panel, referred to as “methRisk”, and validated its predictive power using the Reduced Representation Bisulfite Sequencing data of HCC tumor tissue samples from 29 surgically resected patients. To assess the noninvasive prognostic value of these markers, we collected plasma cfDNA samples from an independent validation cohort of 52 HCC patients, and profiled the methylation patterns of these samples using our newly developed cost-effective cfDNA methylome sequencing assay, cfMethyl-Seq. We utilized random survival forest models combined with 10-fold cross-validation to predict the methRisk using the circulating markers. The cfDNA-based methRisk effectively stratifies patients into clinically relevant risk groups and predicts patient survival with high accuracy (3-year AUC = 0.81, 95% CI: 0.68-0.94). Integrating the cfDNA-based methRisk with existing risk indices like the Barcelona clinic liver cancer (BCLC) staging greatly improves the noninvasive prognostic assessments (3-year AUC = 0.91, 95% CI: 0.80-0.99). In summary, these findings indicate that cfDNA methylation is a promising noninvasive prognostic biomarker for HCC, providing a proof-of-concept for its potential clinical utility. Incorporating cfDNA methylation analysis into the existing noninvasive prognostic framework for HCC patients holds great potential for enhancing the effectiveness of current staging systems and optimizing patient selection for curative therapies like liver transplantation.
Citation Format: Ran Hu, Benjamin Tran, Shuo Li, Mary L. Stackpole, Weihua Zeng, Yonggang Zhou, Andrew Melehy, Xianghong Zhou, Wenyuan Li, Vatche Agopian. Cell-free DNA methylation as a noninvasive prognostic biomarker in hepatocellular carcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr LB103.