Ready-to-use ELISA kits are available for the detection of Ki-1/57, an alias of the protein, hyaluronan binding protein 4. The official gene symbol is HABP4. The protein, with a mass of 45.8 kDa and length of 413 residues, is reported to be cytoplasmic and nuclear. It may be known by other names, including: Ki-1/57, IHABP4, ki-1/57 intracellular antigen, intracellular antigen detected by monoclonal antibody Ki-1, and intracellular hyaluronan-binding protein 4.