A) Within thymic mTECs, Aire drives the expression of antigens (Ag) shared between tumors and normal (self) tissues. These antigens are then presented by mTECs, or dendritic cells (DCs) by antigen transfer, to developing thymocytes in the thymus. Recognition of self/tumor antigens by thymocytes results in 2 potential fates: clonal deletion (red “X”) of conventional T cells capable of tumor eradication or diversion into the immunosuppressive Treg lineage, reducing antitumor immunity. TCR: T-cell receptor; MHC: major histocompatibility complex. B) Decreased Aire expression predisposes to autoimmunity but also enhances antitumor immunity, whereas increased Aire expression prevents autoimmunity but restricts antitumor immunity.