Molecular biomarkers for early-stage hepatocellular carcinoma: Clinical applications beyond alpha-fetoprotein

Hepatocellular carcinoma (HCC) remains a leading cause of cancer-related death worldwide, owing to late-stage diagnosis and underlying liver disease that limits curative treatment options. Conventional surveillance and diagnostic strategies relying on imaging and alpha-fetoprotein (AFP) lack sufficient sensitivity, particularly for early-stage disease, underscoring the need for more accurate and minimally invasive approaches. Liquid biopsy has emerged as a promising investigational approach for early HCC detection and disease monitoring by enabling analysis of tumor-derived components in circulation. This review summarizes recent advances in liquid biopsy biomarkers for early-stage HCC, including genomic alterations in circulating tumor DNA (ctDNA), DNA methylation markers, circulating microRNAs, exosome-derived non-coding RNAs, and inflammatory markers. Established biomarkers such as AFP, together with complementary biomarkers including PIVKA-II, contribute to HCC risk assessment, while ctDNA alterations, particularly TERT promoter and TP53 mutations, provide insight into early tumorigenesis and molecular heterogeneity. Aberrant methylation of tumor suppressor genes, including RASSF1A, SEPT9, and CDKN2A, represents early molecular events detectable in plasma. Circulating and exosomal microRNAs and long non-coding RNAs (lncRNAs) have demonstrated potential to improve diagnostic accuracy, particularly when incorporated into multi-marker panels. Importantly, these biomarkers vary in their level of clinical validation, ranging from guideline-integrated markers to emerging candidates that still require further standardization and prospective validation. Integrating validated biomarkers with novel epigenetic and RNA-based signatures holds substantial promise for improving early detection, patient stratification, and therapeutic decision-making in HCC.