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.