B7x was identified by Sica et al[2] through bioinformatics in 2003, and Salceda et al[3] found that B7x mRNA and protein overexpression in human breast and serous ovarian cancer further confirmed the existence of B7x, whose gene is mapped to the human 1p11.1 gene cluster. The gene discussed is VTCN1; the disease is ovarian serous adenocarcinoma.