It is also possible to use Nbs targeting immune checkpoints (since blocking CD279 and CD274 un-suppresses T-cell apoptosis and upregulates antitumor responses) or to conjugate a tumor-antigen specific Nb to a toxin for endocytosis into the tumor cell (fusion of Pseudomonas exotoxin A to a Nb specific to vascular endothelial growth factor 2) [130,131]. The gene discussed is PDCD1; the disease is neoplasm.