A substance being studied in the treatment of liver cancer. HuAFP31 is a monoclonal antibody that can bind to tumor cells that make a protein called alpha fetoprotein (AFP). It is linked to a radioactive substance called yttrium Y 90, which may help kill the cancer cells. Yttrium Y 90 DOTA monoclonal antibody HuAFP31 is a type of radioimmunoconjugate.