Beyond VEGF: AEG-1/MTDH as a Systems-Level Orchestrator of Angiogenesis in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) remains one of the leading causes of cancer-related mortality worldwide and is characterized by extensive vascularization, aggressive progression, and limited therapeutic responsiveness. Angiogenesis plays a central role in HCC development by supporting tumor growth, metabolic adaptation, invasion, and metastatic dissemination. Although anti-angiogenic therapies targeting the vascular endothelial growth factor (VEGF) pathway have improved clinical management, their overall survival benefit remains modest because of compensatory signaling, adaptive resistance, and the highly complex nature of the tumor microenvironment (TME). Astrocyte elevated gene-1/metadherin (AEG-1/MTDH) has emerged as a multifunctional oncogene that functions by orchestrating interconnected angiogenic, inflammatory, metabolic, and immune-regulatory programs within the hepatic tumor microenvironment. AEG-1 regulates angiogenesis through modulation of VEGF-family signaling, NF-κB activation, hypoxia-responsive pathways, PI3K/AKT signaling, endothelial remodeling, and translational control of pro-angiogenic mediators. Emerging evidence further implicates AEG-1 in hypoxia adaptation, immune evasion, extracellular vesicle signaling, and metabolic reprogramming, supporting its role as a systems-level regulator of HCC angiogenesis. This review summarizes the current understanding of the molecular mechanisms through which AEG-1 regulates angiogenesis in HCC, discusses its interactions with the TME and anti-angiogenic resistance pathways, and highlights future translational opportunities for developing multi-targeted therapeutic strategies beyond conventional VEGF-centric approaches.