Oncofetal MCB1 Is a Functional Biomarker for HCC Personalized Therapy.

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide and lacks biomarkers for personalized therapy. Herein, it is reported that MCB1 could be a novel oncofetal protein that is upregulated in the preneoplastic lesions and serum of early HCC patients. Functional studies reveal that MCB1 modulated p53 protein degradation to promote T-IC generation and drive HCC initiation. Furthermore, the MCB1/p53 axis is shown to determine the responses of hepatoma cells to conventional chemotherapeutics and predict transcatheter arterial chemoembolization (TACE) benefits in patients. Importantly, MCB1 can mediate sorafenib/lenvatinib resistance by downregulating two essential drug targets fibroblast growth factor receptor 1 (FGFR1) and vascular endothelial growth factor receptor 3 (VEGFR3) expression in a proteasome-dependent manner. Patient-derived tumor organoids (PDOs), patient-derived xenografts (PDXs), and patient cohorts analysis suggested that MCB1 levels in HCCs may determine the distinct responses to conventional therapeutics and targeted drugs. Furthermore, treatment of targeted drugs-resistant HCC with adeno-associated virus (AAV) targeting MCB1 or a proteasome inhibitor restores targeted drug response, suggesting their clinical significance in HCC combinational therapy. In conclusion, these findings demonstrate that MCB1 could act as a driver for HCC initiation, a contributor to drug resistance, and a biomarker for individualized HCC therapy.