Materials and methods for treating hepatocellular carcinoma in a mammal are disclosed. The methods comprise administering to a mammal a composition comprising a therapeutically effective amount of a zvegf3 antagonist in combination with a pharmaceutically acceptable delivery vehicle. Zvegf3 antagonists include anti-zvegf3 antibodies, mitogenically inactive receptor-binding zvegf3 variant polypeptides, and inhibitory polynucleotides.