MICB (Human Histocompatibility Complex Class I associated Gene B) is a transmembrane glycoprotein as a ligand for human NKG2D type II receptor. The MICB gene is located in the MHC-I class region of human chromosome 6 and is polymorphic, with more than 15 known human alleles. MICB is expressed only in trace amounts in normal cells, it is usually expressed in epithelial tumors and can be induced by bacterial and viral infections. Therefore, the identification of MICB is closely related to tumor surveillance, viral infection and the prevention of autoimmune diseases.