ErbB3, also called Her3 (human epidermal growth factor receptor 3), is a type I membrane glycoprotein that is a member of the ErbB family of tyrosine kinase receptors. ErbB family members serve as receptors for the epidermal growth factor (EGF) family of growth factors. Among ErbB family members, ErbB3 is unique in that it contains a defective kinase domain. ErbB3 is expressed in keratinocytes, melanocytes, skeletal muscle cells, embryonic myoblasts and Schwann cells. Monomeric ErbB3 serves as a low affinity receptor for the heregulins (HRG). rhErbB3-f is a recombinant genetic engineering product which expressed in E. Coli. RhErbB3-f can induce specific antibody production in vivo, hence to inhibit tumor cell growth. The product can be used to treat early, medium and advanced or post-operative breast cancer patients with over-expression of ErbB2. According to its mechanism of action, rhErbB3-f is classified into therapeutic cancer vaccine. Synonym: ErbB3 Fragment (ErbB3-f), Human. Formulation: A white, semitransparent suspension, the normal content of each vial is 1 mg of rhErbB3-f, 1mg aluminum hydroxide and small amount of arginine, sodium chloride, sodium phosphate, and potassium phosphate.