Abstract
B7-H4 (B7x, B7S1, VTCN1, DD-0110) is a member of the B7 superfamily that negatively regulates T cell responses.(1) In addition, B7-H4 expression is increased on tumors and has been shown to be a negative prognostic marker for many cancers.(2) Unexpectedly our recent study demonstrated that B7-H4 inhibited tumor growth and was required to promote effective antitumor responses.(3).